Login| Sign Up| Help| Contact|

Patent Searching and Data


Title:
POLYNORBORNENYL POLYMERS COMPRISING ELECTRON TRANSPORTING SIDE GROUPS
Document Type and Number:
WIPO Patent Application WO/2012/088322
Kind Code:
A1
Abstract:
The various inventions and/or their embodiments disclosed herein relate to polynorbornenyl polymers comprising phenanthroline electron transporting side groups. They relate also to compositions comprising a blend of polynorbornenyl polymers as above described with polynorbornenyl polymers comprising arylamine hole carrying side groups. The blend compositions are useful as host materials for luminescent guests, which are capable of carrying holes, electrons, and excitons into contact with the luminescent guests, for making the emissive layers of electronic devices such as organic light emitting diodes (OLEDs).

Inventors:
ZHANG JUNXIANG
CAI DENGKE (US)
MARDER SETH (US)
KIPPELEN BERNARD (US)
Application Number:
PCT/US2011/066606
Publication Date:
June 28, 2012
Filing Date:
December 21, 2011
Export Citation:
Click for automatic bibliography generation   Help
Assignee:
GEORGIA TECH RES INST (US)
ZHANG JUNXIANG
CAI DENGKE (US)
MARDER SETH (US)
KIPPELEN BERNARD (US)
International Classes:
C08G61/08; C08L65/00
Domestic Patent References:
WO2010021929A22010-02-25
WO2009026235A22009-02-26
WO2009080799A22009-07-02
WO2009080797A12009-07-02
Foreign References:
US20050182220A12005-08-18
EP2010058728W2010-06-21
US20060127696A12006-06-15
US20060127696A12006-06-15
Other References:
REZVANI A ET AL: "Ruthenium (II) Dipyridoquinoxaline-Norbornene: Synthesis, Properties, Crystal Structure and Use as a ROMP Monomer", INORGANIC CHEMISTRY, AMERICAN CHEMICAL SOCIETY, EASTON, US, vol. 43, no. 16, 1 January 2004 (2004-01-01), pages 5112 - 5119, XP003004891, ISSN: 0020-1669, DOI: 10.1021/IC0498438
FABIAN NIEDERMAIR ET AL: "Solution Self-Assembly and Photophysics of Platinum Complexes Containing Amphiphilic Triblock Random Copolymers Prepared by ROMP", ORGANOMETALLICS, vol. 28, no. 9, 11 May 2009 (2009-05-11), pages 2888 - 2896, XP055024022, ISSN: 0276-7333, DOI: 10.1021/om900083n
DUAN ET AL., J.MATER. CHEM, vol. 20, 2010, pages 6392 - 6407
ZAAMI ET AL., MACROMOL. CHEM. PHYS., vol. 205, 2004, pages 523 - 529
LIAW, JOURNAL OF POLYMER SCIENCE: PART A: POLYMER CHEMISTRY, vol. 45, 2007, pages 3022 - 3031
YANG, MEERHOLZ ET AL., ADV. MATER., vol. 18, 2006, pages 948 - 954
FORSTNER, A., ANGEW. CHEM., INT. ED., vol. 39, 2000, pages 3013
T. M. TMKA; GRUBBS, R. H., ACC. CHEM. RES., vol. 34, 2001, pages 18
ZHANG ET AL., SYNTHESIS, 2002, pages 1201
DOMERCQ ET AL., CHEM. MATER., vol. 15, 2003, pages 1491
Y. KAWAMURA ET AL., APPL. PHYS. LETT., vol. 86, 2005, pages 071104,1
T. SAJOTO ET AL., LNORG. CHEM., vol. 44, 2005, pages 7992 - 8003
C. H. YANG ET AL., ANGEW. CHEM. INT. ED., vol. 46, 2007, pages 2418 - 2421
H. WU ET AL., ADV. MATER., vol. 20, no. 4, 2008, pages 696 - 702
Attorney, Agent or Firm:
RUTT, J. Steven et al. (3000 K Street NWSuite 60, Washington District of Columbia, US)
Download PDF:
Claims:
What is claimed is:

1. A norbornenyl polymer or copolymer comprising a plurality of subunits having a structure:

wherein

L2 is an organic linking group, and

Rox comprises at least one optionally substituted phenanthroline group comprising a structure

wherein

each Ra or Rb, group is independently selected from hydrogen, fluoride, one or more linear or branched C1.20 alky I, fluoroalkyl, alkoxy, fluoroalkoxy, aryl, or heteroaryl groups, and

each x is an independently selected integer 0, 1 , or 2.

2. The norbornenyl polymer or copolymer of claim 1 , wherein the at least one optionally substituted henanthroline group comprises the structure

3. The norbornenyl polymer or copolymer of claim 1 , wherein the at least one optionally substitut up comprises the structure

4. The norbornenyl polymer or copolymer of claim 1 , wherein the at least one optionally substituted phenanthroline group comprises the structure

5. The norbornenyl polymer or copolymer of claim 4, wherein each x is

0.

6. The norbornenyl polymer or copolymer of any one of the preceding claims, wherein each Ra is hydrogen.

7. The norbornenyl polymer or copolymer of any one of the preceding claims, wherein each Rb group is independently selected from fluoride, one or more linear or branched C| .2o alkyl, fluoroalkyi, alkoxy, fluoroalkoxy, aryl, or heteroaryl groups.

8. The norbornenyl polymer or copolymer of claim 7, wherein each Rb group is independently selected from one or more linear or branched C 1.20 alkyl groups.

9. The norbornenyl polymer or copolymer of any one of the preceding claims wherein Ra is hydrogen and at least one Rb is t-butyl.

10. The norbornenyl polymer or copolymer of any one of the preceding claims wherein L2 has the structure

I— <CH2)z— I ^(CH2) °^(CH2)z-r

J -1 ί

wherein z and z' are independently selected integers 0, 1 , 2, 3, 4, 5, 6, 7, 8, 9, 10, 1 1 , or 1 2.

1 1 . The norbornenyl polymer or copolymer of claim 1 0 wherein L" has t. t h !-o-iCHzk-l

the structure .

12. The norbornenyl polymer or copolymer of claim 10 or 1 1 wherein z and z' are independently selected integers 1 , 2, 3, 4, 5, 6, 7, 8, 9, 10, 1 1 , or 12.

1 3. The norbornenyl polymer or copolymer of any one of the preceding claims, which comprises a plurality of subunits of the structure

14. The norbornenyl polymer or copolymer of any one of the preceding claims, which is a homopolymer.

1 5. A composition comprising a blend of

at least one first norbornenyl polymer or copolymer comprising one or more norbomenyl subunits in the polymer backbone linked to at least one optionally substituted arylamine hole transporting side group, and

at least one additional norbomenyl polymer or copolymer comprising one or more norbomenyl subunits in the polymer backbone linked to at least one optionally substituted electron transporting side group,

wherein said additional norbomenyl polymer or copolymer is the norbomenyl polymer or copolymer according to any one of the preceding claims.

16. The composition of claim 1 5 wherein the weight ratio of the first norbomenyl polymer to the additional norbornenyl polymer is from about 1 : 5 to about 5: 1.

1 7. The composition of claim 1 5 or 1 6 wherein the first norbornenyl polymer is a homopolymer wherein each norbornenyl subunit is linked to an optionally substituted monocarbazole, biscarbazole, triscarbazole or triarylamine side group.

1 8. The composition of claim 1 5 or 1 6 wherein the first norbornenyl polymer or copolymer comprises a plurality of subunits having the structure

wherein

L 1 is an organic l inking group, and

(b- 1 ) R° comprises at least one optionally substituted carbazole group

wherein :

R1 , R2, R4, R5, R6, R7 are independently selected from a l inear or branched C1-C12 alkyl group or H;

R3 is a linear or branched C1-C12 alkyl group, a phenyl, bisphenyl or a phenyl-pyridyl group, or H;

(b-2) Rc comprises at least one optionally substituted carbazole group comprising the structure:

wherein:

R'and R2 are independently selected from a linear or branched C1-C12 a group or H, and

R3 is a linear or branched C1-C12 alkyl group, a phenyl, bisphenyl or a phenyl-pyridyl group or H;

(b-3) Rc comprises at least one optionally substituted triarylamine group comprisin

wherein:

R1, R2, R4, R5 is a linear or branched C1-C12 alkyl group or H; or (b-4) Rc comprises at least one optionally substituted triscarbazole group comprising the structure:

wherein:

R1 , R2, R4, R5 is a l inear or branched C1 -Q 2 alkyl group or H.

19. The composition of claim 1 8 wherein each of R1 , R2, R4, R5, R6 and R7 are hydrogen.

20. The composition of any one of claims 1 5 to 1 9 further comprising a non-polymeric lum inescent guest em itter, such as a metal complex wherein the metal is Re, Ru, Os, Rh, Ir, Pd, Pt, Cu or Au.

21 . An electronic device comprising the composition of any one of claims 1 5 to 20.

22. The electronic device of claim 21 that is a l ight emitting diode.

23. The electronic dev ice of claim 22 wherein the light emitting diode comprises an em ission layer that comprises the composition.

24. Use of the norbornenyl polymer or copolymer according to any one of claims 1 to 14 for transporting electrons in an electron transport layer of an organic light em itting diode.

25. Use of the composition according to any one of claims 15 to 19 as hole and/or electron transporting host for a luminescent guest emitter in the emission layer of an organic light emitting diode.

Description:
Polynorbornenyl Polymers Comprising Electron Transporting Side Groups

STATEMENT OF GOVERNMENT LICENSE RIGHTS

[0001 ] The inventors received partial funding support through the STC Program of the National Science Foundation under Agreement Number D R-020967 and the Office of Naval Research through a MURI program, Contract Award Number 68A- 1060806. The U.S. Government has certain rights in the invention.

TECHNICAL FIELD OF THE INVENTION

[0002] The inventions disclosed and described herein relate to polynorbornenyl polymers comprising electron carrying or transporting side groups. They relate also to compositions comprising a blend of polynorbornenyl polymers comprising electron carrying or transporting side groups with polynorbornenyl polymers comprising hole carrying side groups; the compositions are useful as host materials for lum inescent guests, materials which are capable of carrying holes, electrons, and excitons into contact with the luminescent guests, and for making the em issive layers of electronic devices such as organic light em itting diodes (OLEDs).

BACKGROUND OF THE INVENTION

[0003] Considerable research has been directed toward the synthesis of organic light-emitting diodes (OLEDs), in view their potential applications in full-color flat panel d isplays and solid state lighting. Such OLEDs often contain a light emissive layer comprising a lum inescent material as a guest, dispersed and/or dissolved in a mixture of host/carrier materials capable of transporting holes, electrons, and/or excitons into contact with the lum inescent guest. The lum inescent guest is excited by the electrons, holes, and/or excitons formed on the host, and then emits light. The light emissive layer is typically d isposed between an anode and cathode.

[0004] Single layer OLED devices are known, but typical ly exhibit very low efficiencies and lifetimes, for a variety of reasons. Efficiency has been dramatical ly improved in some cases by employing additional layers of materials in the OLED devices, such as an additional layer comprising a material whose properties are optim ized for transporting holes into contact with the emission layer, and/or an additional electron transport layer comprising a material whose properties are optim ized for carrying electrons into contact with the emission layer, Upon application of voltage/current across the OLED devices, holes and electrons are transported through the intermediate layers and into the emissive layer, where they combine to form excitons in the host material, and/or stimulate the formation of excited states of the luminescent guest material.

[0005] High-performance phosphorescent OLEDs with good short term luminescence and efficiency have been reported, at least for green and red/orange emitters, see further discussions below However most of the best prior art devices employ small molecule components that are fabricated by expensive multilayer vacuum thermal evaporation processes. For example, materials comprising small molecule carbazoles have been utilized as hole transporting and/or electron blocking materials in OLED applications, and as hosts for guest emitters in OLED emissive layers. Examples of known small molecule carbazole-based hole-transporting materials are shown below. Solution processable polymeric carbazoles such as polyvinylcarbazole ("PVK") are also known for use as the hole transporting layers, and as hosts for guest emitters in the emissive layers of OL

9-methyl-9H-carbazole

[0006] A recent article by Duan et al (J. Mater. ChenY. 2010, 20, 6392-6407) reviewed the status of "Solution Processable Small Molecules for Organic Light Emitting Diodes, hereby incorporated by reference herein, described a number of the characteristics and structures of known hole transporing small molecules, as shown below;

SpiwMvOT.Mt ηνλΙΤΙΜΤΛ

[0007] Duan et al described major advances in the area of OLEDs based on solution processable small molecules, but concluded that "There is a long way to go for solution processed OLEDs based on small molecules to fully demonstrate their potentials for ubiquitous and low cost displays and lightings." However Duan et al also noted that the state of the art is even more difficult for solution processed polymers, which typically have difficulty self ordering in the solid state as easily as small molecules do. [0008] Polynorbornenyl polymers and copolymers having l inked side chains comprising carbazole groups have been reported, see for example Zaam i et al, Macromol. Chem. Phys. 2004, 205, 523-529, and Liaw et al, (Journal of Polymer Science: Part A : Polymer Chem istry, Vol. 45, 3022-303 1 (2007), and US Patent Publication 2005/01 82220. Use of such carbazole-linked polymers in OLED applications gives significant potential to employ low cost solution and/or ink-jet printing processes for making the OLEDs, wh ich can be very important for potential large area and/or low cost applications, but the fabrication of efficient multi-layer OLED devices wherein all the layers are deposited by solution processes sti ll suffer serious l im itations and remain a big chal lenge.

[0009] Recently, WO 2009/026235 and WO 2009/080799, hereby incorporated by reference herein, reported norbomenyl homopolymers, copolymers, and corresponding norbornene monomers comprising one, two or three linked carbazole groups. Norbomenyl homopolymers comprising tris carbazole groups, such as CZ-I-25 whose structure is shown below, were used in the hole-transporting layers in OLEDs to give external quantum efficiencies as high as about 1 8.5%. CZ- I-25 was also used as a host (for green emitters) in OLED emissive layers to give external quantum efficiencies as h igh as about 5-6%.

[00010] Correspondingly, small-molecule oxadiazoles (PBD and OXD-7), triazoles (TAZ), benzimidazoles (TPBI), and pyridines such as those shown below are well known materials for use in making electron transporting layers for OLED devices

B3PyPB

[0001 1 ] Furthermore, solution processable polymeric or copolymeric norbornenyl- linked oxadiazoles have also been reported for use as both electron transporting materials and as host materials for guest em itters in OLEDs. See for example WO 2009/080797, hereby incorporated herein by reference. When polynorbornenyl- oxadiazoles such as YZ-I-293 (structure show below) were blended with the vinyl ic carbazole polymer PVK, and used as a host for small molecule green em itters, moderately bright devices showing external quantum efficienc ies in the range of 10- 14% were obtained. [0001 2] Recently, some of the Applicants filed PCT Patent Application PCT EP2010/058728, hereby incorporated by reference herein, which disclosed certain ambipolar polymers and copolymers that comprised both oxad iazole and carbazole groups, and described their uses in OLED emissive layers. One such class of ambipolar homopolymers had monomer subunits that comprised both oxadiazole and carbazole subunits, whose structure is shown below;

wherein at least one of the R 1 , R 2 and R 3 groups comprise an optional ly substituted carbazole group having the structure

[0001 3] PCT Patent Appl ication PCT/EP201 0/058728 also disclosed a different class of ambipolar norbomenyl copolymers that have at least some subun its having each of the stru

(IVa) wherein L 1 and L 2 are independently selected C1 -C20 organic linking groups,

R c comprises at least one carbazole group, and

R°* comprises at least one 2-phenyl-5-phenyl- l ,3 ,4-oxadiazole group.

[00014] Yang, Meerholz et al (Adv. Mater. 2006, 1 8, 948-954) d isclosed that an OLED employing an em issive layer comprising a blend of the polymeric carbazole PV with the PBD small molecule oxadiazole and Ir(mppy)3 guest emitter gave current efficiencies up to 67 cd/A and EQE of 1 8.8% at 1 00 caVm 2 , and 56 cd/A and EQE of 1 5.7% at l OOO cd/m 2 .

[0001 5] Very recently, in a June 2010 public presentation at a LOPE-C meeting in Frankfurt (but without providing significant details), ruger et al reported an OLED with an em issive layer that used a blend of vinylic homopolymers comprising carbazole hole carriers and benzimidazole electron carriers (structures shown below), which yielded green OLEDs with current efficiencies up to about 40 cd/A, and luminance up to about 10,000 cd 2 .

[00016] Nevertheless, devices based on mixtures of hole carrying and electron carrying materials in their em ission layers, whether based on mixtures of small molecules, and/or polymers may undergo phase separations, undesirable partial crystal lizations, and/or otherwise degrade upon extended OLED device heating, decreasing OLED device efficiency and/or lifetimes over time.

[0001 7] Accord ingly, there remains a need in the art for improved host materials that can very efficiently function as guest materials that transport holes, electrons, and/or exc itons into contact with phosphorescent guests in em ission layers, without undergoing undesirable phase separations, crystall ization, or thermal or chem ical degradation that can cause OLED performance to decline rapidly.

[0001 8] It is to that end that the various embodiments of the inventions described herein relate, in that the various embodiments of the blend compositions comprising blends of norbornenyl polymers comprising hole carrying side groups, and norbornenyl polymers comprising electron carrying side groups described and c laimed herein can serve as hosts materials in OLEDs that provide performance that is among the best yet known, and is unexpectedly superior to the results known for comparable solution processable materials. Moreover Applicants methods and unique polynorbornenyl materials provide a unique and ready method for stabi l izing the polymer blends against undesirable phase separations.

SUMMARY OF THE INVENTION

[00019] The various inventions and/or their embodiments disclosed herein relate to polymer blend compositions comprising a blend of

at least one first norbornenyl polymer or copolymer comprising one or more norbornenyl subunits in the polymer backbone l inked to at least one optionally substituted arylamine hole transporting side group, and

at least one additional norbornenyl polymer or copolymer comprising one or more norbornenyl subunits in the polymer backbone linked to at least one optionally substituted electron transporting side group.

[00020] As will be further elaborated below, the optionally substituted arylam ine hole transporting side groups include for example monocarbazole, biscarbazole, triscarbazole or triarylamine side groups. The optionally substituted electron transporting side groups include for example oxadiazole, phenyl-pyridine, triazole or benzimidazole side groups.

[00021 ] These polymer blend compositions are useful for making organic electronic dev ices, and are particularly useful as hole and/or electron transporting hosts for lum inescent guest emitters, wherein the resulting compositions are typical ly useful for making the em ission layers of organic light em itting diodes, "OLEDs."

[00022] Further detailed description of preferred embodiments of the various monomer precursors, polymers, polymer blends, compositions, and OLED devices wi ll be prov ided in the Detai led Description section below. BRIEF DESCRIPTION OF THE FIGURES

[00023] Figure 1 shows absorption and fluorescent em ission spectra of the polynorbornenyl-oxad iazole homopolymer XH-I-98a, see Example 3.

[00024] Figure 2 shows absorption and fluorescent emission spectra of the polynorbornenyl-triscarbazole homopolymer XH-I-98b, see Example 4.

[00025] Figu re 3 shows absorption and fluorescent emission spectra of the random copolymer XH-I-41 comprising 1 : 1 bis oxadiazole/triscarbazole groups, see

Example 5.

[00026] Figure 4 shows absorption and fluorescent emission spectra of the random copolymer XH-l-53c comprising 3 :2 bis oxad iazole/triscarbazole groups, see Example 6.

[00027] Figure 5 shows absorption and fluorescent emission spectra of the diblock copolymer XH-I-68a comprising 1 : 1 bis oxadiazole/triscarbazole groups, see Example 7.

[00028] Figure 6 shows solution absorption and fluorescent em ission spectra in CH2CI2 of a 1 : 1 blend of the polynorbornenyl-bisoxadiazole homopolymer XH-I-98a with the polynorbornenyl-triscarbazole homopolymer XH-I-98b, see Example 8.

[00029] Figure 7a a schematic device configuration for an OLED device described in Example 9, which employs a 1 : 1 blend of the homopolymer XH-I-98a with the homopolymer XH-I-98b, and 6% lr(ppy)3 in its emissive layer. Figure 7b shows the current density versus voltage characteristics of the OLED, and Figure 7c shows the lum inescence and external quantum efficiency of the OLED versus voltage.

[00030] Figure 8a a schematic device configuration for an OLED device described in Example 1 0, which employs a 1 : 1 blend of the homopolymer XH-I-98a with the homopolymer XH-I-98b, and 1 2% Ir(ppy)3 in its emissive layer. Figure 8b shows the current density versus voltage characteristics of the OLED, and Figure 8c shows the lum inescence and external quantum efficiency of the OLED versus voltage.

[0003 1 ] Figure 9a a schematic device configuration for an OLED device described in Example 1 1 , which employs a 1 .5 : 1 blend of the homopolymer XH- l-98a with the homopolymer XH-I-98b and 6% Ir(ppy)3 in its em issive layer. Figure 9b shows the current density versus voltage characteristics of the OLED, and Figure 9c shows the lum inescence and external quantum efficiency of the OLED versus voltage. [00032] Figure 10a a schematic device configuration for an OLED device described in Example 12, which employs a 1 : 1 .5 blend of the homopolymer XH-I-98a with the homopolymer XH-I-98b and 6% lr(pppy) 3 in its emissive layer. Figure 10b shows the current density versus voltage characteristics of the OLED, and Figure 10c shows the lum inescence and external quantum efficiency of the OLED versus voltage.

[00033] Figure 1 1a a schematic device configuration for an OLED device described in Example 1 3, which employs a 1 : 1 .5 blend of the homopolymer XH-I-98a with the homopolymer XH- I-98b and 6% FIrpic in its emissive layer. Figure l i b shows the current density versus voltage characteristics of the OLED, and Figure 11c shows the lum inescence and external quantum efficiency of the OLED versus voltage.

[00034] Figure 12a a schematic device configuration for an OLED dev ice described in Example 14, which employs a 1 : 1 .5 blend of the homopolymer XH-I-98a with the homopolymer XH-I-98b and 12% FIrpic in its em issive layer. Figure 12b shows the current density versus voltage characteristics of the OLED, and Figure 12c shows the lum inescence and external quantum efficiency of the OLED versus voltage.

[00035] Figure 13a a schematic device configuration for an OLED device described in Comparative Example 1 5, which employs a random norbornenyl copolymer XH-I-41 comprising 1 : 1 bisoxadiazole and triscarbazole side chains in its em issive layer. Figure 13b shows the current density versus voltage characteristics of the OLED, and Figure 13c shows the lum inescence and external quantum efficiency of the OLED versus voltage.

[00036] Figu re 14a a schematic device configuration for an OLED device described in Comparative Example 16, which employs a random norbornenyl copolymer XH-l-53c comprising 3 :2 bisoxadiazole and triscarbazole side chains in its emissive layer. Figure 14b shows the current density versus voltage characteristics of the OLED, and Figu re 14c shows the lum inescence and external quantum efficiency of the OLED versus voltage.

[00037] Figure 15a a schematic device configuration for an OLED dev ice described in Comparative Example 1 7, which employs a diblock norbornenyl copolymer XH-I-68a comprising 1 : 1 bisoxadiazole and triscarbazole side chains in its em issive layer. Figure 15b shows the current density versus voltage characteristics of the OLED, and Figu re 15c shows the luminescence and external quantum efficiency of the OLED versus voltage.

[00038] Figu re 16a a schematic dev ice configuration for an OLED device described in Comparative Example 1 8, which employs a random styrenyl copolymer YZ- rV-25 comprising 1 : 1 bisoxadiazole and triscarbazole side chains in its emissive layer. Figure 16b shows the current density versus voltage characteristics of the OLED, and Figure 16c shows the lum inescence and external quantum efficiency of the OLED versus voltage.

[00039] Figure 17a a schematic device configuration for an OLED device described in Comparative Example 19, which employs an ambipolar styrenyl homopolymer YZ-IV- 13 comprising both oxadiazole and carbazole groups in its em issive layer. Figure 17b shows the current density versus voltage characteristics of the OLED, and Figure 17c shows the lum inescence and external quantum efficiency of the OLED versus voltage.

[00040] Figure 18a a schematic device configuration for an OLED device described in Comparative Example 20, wh ich employs an ambipolar styrenyl homopolymer YZ-rV-21 comprising one oxadiazole and two carbazole groups in its emissive layer. Figu re 18b shows the current density versus voltage characteristics of the OLED, and Figure 18c shows the luminescence and external quantum efficiency of the OLED versus voltage.

DETAILED DESCRIPTION OF THE INVENTION

[00041 ] The various inventions and/or their embodiments disc losed herein relate to and include norbornenyl polymers, copolymers, polymer blends, and blend compositions that are useful as host materials for lum inescent guests, which are capable of carrying holes, electrons, and excitons into contact with the lum inescent guests, for making the em issive layers of electronic devices such as organic l ight em itting diodes (OLEDs).

The Norbornenyl Monomers and Polymers

[00042] The inventions described and claimed herein relate to polymer blend compositions comprising at least two different types of polymers or copolymers, at least one first norbomenyl polymer or copolymer comprising one or more norbomenyl subunits in the polymer backbone linked to at least one optionally substituted arylamine hole transporting side group, and

at least one additional norbomenyl polymer or copolymer comprising one or more norbomenyl subunits in the polymer backbone linked to at least one optionally substituted electron transporting side group.

[00043] In many embodiments of the invention, the first norbomenyl- polymer or copolymer is a homopolymer consisting essentially of norbomenyl subunits in the polymer backbone, wherein each norbomenyl subunit is linked to at least one optionally substituted arylamine hole transporting side group.

[00044] Similarly, in many embodiments of the invention, the additional norbomenyl polymer or copolymer is a homopolymer consisting essentially of norbomenyl subunits in the polymer backbone wherein each norbomenyl subunit is linked to at least one optionally substituted electron transporting side group. Such homopolymers can be conceptually envisioned as having the generic structures shown below.

(Norbomenyl Subunit) n (Norbomenyl Subunit),,

Linking Group Linking' Group

One or More Hole Transporting Groups One or More Electron Transporting Groups

[00045] In some preferred embodiments of the polymer blend compositions of the invention,

the first norbomenyl polymer or copolymer is a homopolymer comprising norbomenyl subunits in the polymer backbone linked to at least one optionally substituted monocarbazole, biscarbazole, or triscarbazole side group, and

the additional norbomenyl polymer or copolymer is a homopolymer comprising norbomenyl subunits in the polymer backbone linked to at least one optionally substituted oxadiazole side group.

[00046] In many embodiments, the at least one first norbomenyl polymer or copolymer of the blend compositions typically comprises one or more, or at least a plurality of norbomenyl subunits in the polymer backbone having the structure a) L 1 is the organic linking group, and

b) R c comprises at least one optionally substituted arylam ine hole

transporting side group.

[00047] In many embodiments, the at least one additional norbornenyl polymer or copolymer of the blend compositions typically comprises one or more, or at least a plural ity of norbornenyl subunits in the polymer backbone having the structure

wherein

a) L 2 is an organic linking group, and

b) R o comprises at least one optionally substituted electron transporting side group.

[00048] The nature of the linking groups will now be further described below.

[00049] The organ ic linking groups, including L 1 and L 2 , are typically independently selected normal, branched, or cycl ic divalent organic groups that can be selected from organic groups that are thermally, chemically, and electrochem ical iy stable under the conditions of operation of organic electronic devices such as OLEDs, and include for example but not l im ited to alkylenes, cycloalkyls, ethers, carboxylate esters, arylenes, arylene oxides, heteroarylenes, hetereroarylene oxides, and the l ike, and combinations thereof.

[00050] In many embodiments, the organic linking groups, including L 1 and/or L 2 , comprise from C 1 -C20 carbon atoms, or C 1 -C 12 carbon atoms, or C 1 -C6 carbon atoms. The organ ic linking groups can be optional ly substituted with substituent groups such as but not limited to one or more fluorides, alkyl groups ether groups, aryls, heteroaryls, and the like.

[0005 1 ] In many embodiments, the L 1 and/or L 2 organic linking groups can be independently selected from the structures

\— (CH 2 ) Z -| ^(CH 2 ) z ^° (CH 2 ) z - ^

^-0-(CH 2 ) z -^ or }— (CH 2 ) Z — O— | wherein z and z' are independently selected integers 0, 1 , 2, 3, 4, 5, 6, 7, 8, 9, 10, 1 1 , or 1 2.

[00052] The optionally substituted arylam ine hole transporting side groups such as the R c groups recited above, as noted by Duan et al,"should have electron donating moieties to form stable radical cations," so as to be able to transport holes (formed by removal of an electron to leave behind a reasonably stable rad ical cation). Duan et al noted that "molecules with phenylam ine groups have gained much research attention due to their high hole drift mobi lities. . . " Appl icants concur with that accessment, but view such groups somewhat more broadly, as including one or more arylamine hole transporting side groups having the general structure of a tertiary amine shown below; wherein at least R a , and possibly Rb and Rc as well are optionally substitute aryl or heteroaryl groups, and R a , Rb and Rc may or may not be joined together to form cycl ic structures. Rb and Rc are not hydrogen, and can be many organic groups, including alkyls of various forms, so the arylam ine hole transporting side groups having the general structure of a tertiary organic am ine group.

[00053] The arylamine hole transporting side groups may be optionally substituted with one or more halides, cyano groups, alkyls, alkoxides, aryls, heteroaryls, and the like. [00054] In many embodiments the arylam ine hole transporting side groups and all the optional substituents comprise from C 1 -C30 carbon atoms, or C 1 -C20 carbon atoms, or C 1 -C 12 carbon atoms.

[00055] The optional ly substituted arylamine hole transporting side groups, including the R groups, include for example monocarbazole, biscarbazole, triscarbazole or triarylamine side groups, or groups combining one or more such groups, and/or other aryl or heteroaryl groups conjugated thereto, any of which can be attached to the linking groups anywhere in their structures.

[00056] Exemplary monocarbazole groups can have structures including the following n -inclusive examples;

wherein R 1 and R 2 can be independently selected from a linear or branched C 1 -C 12 alkyl group or H, and R 3 can be a linear or branched C 1 -C 12 alkyl group, a phenyl, bisphenyl or a phenyl-pyridyl group, or H. It is worth noting that the structure on the right above could also be considered a triarylamine group.

[00057] Monocarbazoles can also have structures such as the following:

wherein R' and R 2 can be independently selected from a linear or branched C 1 -C 12 alkyl group or H, and R 3 can be a l inear or branched C 1 -C 12 alkyl group, a phenyl, bisphenyl or a phenyl-pyridyl group, or H. It is worth noting that this structure could also be considered to comprise a triarylam ine, or a pyridine group.

[00058] Typical biscarbazole groups can have structures including the fol lowing non-inclusive examples;

bisphenyl or a phenyl-pyridyl group, or H. It is worth noting that these compound above could also be considered to comprise triarylamine groups.

[00059] Biscarbazole groups can have structures that incorporate heterocycles such as pyridine groups, such as the following

wherein R'and R can be independently selected from a linear or branched C1 -C 12 alky I group or H, and R 3 can be a linear or branched C1-C12 alky I group, a phenyl, bisphenyl or a phenyl-pyridyl group, or H. It is worth noting that this structure could also be considered to comprise a triarylamine, or a pyridine group.

[00060] Typical triscarbazole groups can have structures including the following non-inclusive examples;

wherein R 1 , R 2 , R 4 and R 5 is a linear or branched C 1 -C12 alky 1 group or H.

[00061 ] Typical triarylam ine groups can have structures including the following non-inclusive ex

wherein R 1 , R 2 , R 4 and R 5 can be a l inear or branched C i -C ? alky I group or H.

[00062] As already noted, the polymer blend compositions described and claimed herein also comprise at least one additional norbornenyl polymer or copolymer comprising one or more norbornenyl subun its in the polymer backbone l inked to at least one optionally substituted electron transporting side group. As noted by Duan et al, "electron transporting materials should have electron accepting moieties to form stable radical anions." Duan et al noted that many of the known electron transporting small molecules suitable for use in OLEDs comprised oxadizole derivatives, pyridine derivatives such as phenanthrol ines, triazole derivatives, im idazole, and benzimidazole derivatives, or combinations thereof.

[00063] Accord ingly, in many embod iments of the inventions described and claimed herein, the optional ly substituted electron transporting side groups include for example, but are not l im ited to oxadiazole derivatives, pyrid ine derivatives such as phenanthrol ines, triazole derivatives, im idazole and benzim idazole derivatives, or combinations thereof, as side groups, such as for example the R ox groups initially described above.

[00064] Suitable oxadiazole derivatives for use as optional ly substituted electron transporting side groups or R o groups include 5-phenyl- l ,3,4-oxad iazole groups or 2,5- diphenyl- 1 ,3,4-oxadiazole groups, as shown below:

wherein each optional R b and R c group can be an independently selected from hydrogen, fluoride, one or more linear or branched C |. 2 o alkyl, fluoroalkyl, alkoxy, or fluoroalkoxy groups, and each x is an independently selected integer 0, 1 , 2, 3 or 4.

"bridged" oxadiazole derivatives suitable at R ox include

wherein each optional R b and R c group can be an independently selected from hydrogen, fluoride, one or more l inear or branched C | . 2 o alkyl, fluoroalkyl, alkoxy, or fluoroalkoxy groups, and each x is an independently selected integer 0, 1 , 2, 3 or 4.

[00066] Very sim ilar triazole derivatives can be formed by replacement of the oxygen atom of the oxadiazole rings with an optionally substituted phenylam ine group, such as for example

wherein the R c group can independently selected from hydrogen, fluoride, one or more linear or branched C | . 2 o alkyl, fluoroalkyl, alkoxy, or fluoroalkoxy groups, and the other

Ra, Rb, and x values can be as previously described above. [00067] Accordingly, in many embodiments of the polymer blends, the additional norbornenyl polymer or copolymer comprises a plurality of oxadiazolyl or triazole subunits having the structure

wherein

L 2 is an organic linking group, and

R ox comprises at least one optional ly substituted oxadiazole or triazole derivative

and Y is a C6-C2 0 aryl or heteroaryl group, and each optional R a , R b and R c group is independently selected from hydrogen, fluoride, one or more l inear or branched C i -20 alkyl, fluoroalkyl, alkoxy, or fluoroalkoxy groups, and each x is an independently selected integer 0, 1 , 2, 3 or 4. [00068] Similarly, in many embodiments of the polymer blends, the additional norbornenyl polymer or copolymer comprises subunits wherein the R o group can be an optionally substituted benzimidazole group comprising the structure

wherein each optional R a , R b , and R c group is independently selected from hydrogen, fluoride, one or more linear or branched C 1.20 alkyl, fluoroalkyl, alkoxy, or fluoroalkoxy groups, and each x is an independently selected integer 0, 1 , 2, 3 or 4.

[00069] The R ox groups can also comprise optionally substituted dimeric or trimeric benzimidazole groups, such as for example the following:

wherein each optional R a and R b group is independently selected from hydrogen, fluoride, one or more linear or branched C 1.20 alkyl, fluoroalkyl, alkoxy, or fluoroalkoxy groups, and each x is an independently selected integer 0, 1 , 2, 3 or 4.

[00070] Suitable optionally substituted electron transporting side groups and/or R ox groups can also include optionally substituted pyridine derivatives.

[00071 ] In many embodiments, such optionally substituted pyridine groups can have other aryl or heteroaryl rings fused thereto, such as for example phenanthroline groups having the structures shown below;

wherein each optional R a or R b , group is independently selected from hydrogen, fluoride, one or more linear or branched C|. 2 o alkyl, fluoroalkyl, alkoxy, fluoroalkoxy, aryl, or heteroaryl groups, and each x is an independently selected integer 0, 1 , or 2.

[00072] Accordingly, in some embodiments, the invention relates to a norbornenyl polymer or copolymer comprising a plurality of subunits having the structure

wherein

a. L 2 is an organic linking group, and

b. R o comprises at least one optionally substituted phenanthroline group comprising the structure

wherein

each optional R a or R b , group is independently selected from hydrogen, fluoride, one or more linear or branched C|.?o alky 1, fluoroalkyl, alkoxy, fluoroalkoxy, aryl, or heteroaryl groups, and

each x is an independently selected integer 0, 1 , or 2.

[00073] Such norbornenyl / phenanthrolinyl copolymers can not only be useful for use in blends with other polymers for emission layers of OLEDs, but may also be useful as such for transporting electrons in OLED electron transport layers.

[00074] Other pyridine derivatives that are known to be capable of serving as electron transporting materials include quinoline derivatives that can include but are not limited t

2-phenylquinolines 2-phenylpyrido[3,2- |quinoxalines

Preparation of the Necessary Monomers, Polymers, and Copolymers

[00075] A variety of norbornenyl monomers linked to arylamine hole transporting side groups such as triarylamines and carbazoles, and norbornenyl monomers linked to electron transporting side groups such oxadiazole, pyridine, triazole, or benzimidazole side groups are known in the art, and many of them could readily be made and used by one of ordinary skill to make polymers or copolymers that are useful as hole-carrying materials, and can be used for making polymer blends or compositions within the scope of the inventions disclosed and claimed herein.

[00076] For example, WO 2009/026235 and WO 2009/080799, hereby incorporated by reference herein for their synthetic teachings regarding relevant norbornenyl monomers and homopolymers, copolymers, and corresponding norbornene monomers comprising one, two or three linked carbazoles, describes a variety of suitable norbornenyl-carbazolyl monomers and homopolymers. Example 1 hereinbelow provides a specific example of the synthesis of a novel norbornenyl-triscarbazolyl monomer (structure shown below), which is useful for synthesizing a corresponding norbornenyl- triscarbazolyl homopolymer (XH-l-98b, polymerization described in Example 4) that is useful for making and illustrating non-limiting examples of the polymer blends disclosed and claimed herein.

[00077] Alternatively, norbomenyl monomers linked to two types of hole carrying biscarbazole groups can be made by the reaction sequences shown below;

or

[00078] Either of the above monomers can be homopolymerized or copolymerized by one of ordinary skill in the art using the typical ROMP polymerization methods described herein.

[00079] Sim ilarly, numerous norbornenyl-l inked oxadiazolyl monomers and corresponding polymers are known in the art as electron-transporting materials, and could be used by one of ordinary ski ll in the art for making the polymer blends of the invention. For example, WO 2009/080797, hereby incorporated by reference herein for its synthetic teachings regard ing relevant norbornenyl monomers and polymers, reported norbornenyl homopolymers, copolymers, and corresponding norbornene monomers comprising two linked oxadiazole groups, discloses a variety of suitable norbornenyl-oxadiazolyl monomers and homopolymers. Example 2 hereinbelow provides a specific example of the synthesis of a norbornenyl-oxadiazolyl monomer (structure shown below) useful for synthesizing a corresponding norbornenyl-oxadiazolyl homopolymer ' (XH-I-98a, polymerization described in Example 3) that is useful for making non-limiting examples of the polymer blends disclosed and claimed herein.

[00080] Many sim i lar norbornenyl monomers comprising arylam ine hole carrying groups can readily be made by those of ordinary skill in the art by sim ilar well known methods. For example, a variety of norbornenyl monomers linked to hole transporting triaryl am ine side groups cou ld be made via the method illustrated below, or by obvious seq

[00081 ] Sim ilarly, a variety of norbornenyl monomers linked to electron transporting benzim idazole side groups can be made via the method i llustrated below, or by obvious alternative sequences of organic reactions well known to those of ordinary ski ll in the art:

[00082] Similarly, a norbornenyl monomer linked to trimeric electron transporting side groups comprising both triarylamine and carbazole groups, such as that shown below can be made v ia the method il lustrated below, or by obvious alternative sequences of organic reactions well known to those of ordinary skill in the art:

[00083] Similarly, a variety of norbornenyl monomers linked to electron transporting triazole side groups could be made via the method illustrated below, or by obvious sequences of well known organic reactions:

[00084] Additionally, various methods could be employed to bond phenanthroline

[00085] Homopolymers derived from any of the above-described norbornenyl monomers can be readily made by ring opening methathesis polymerizations (ROMP) that are well known in the art, which are typically catalyzed by metal complex catalysts well known in the art, including the various "Grubbs" catalysts mentioned below. Random norbornenyl copolymers can also be made by polymerizing mixtures of such norbornenyl monomers (see Examples 5 and 6 below). However, one paricularly attractive feature of norbornenyl polymer chemistry (as compared to largely used free-radical polymerized vinyl monomers such as acrylates, styrenes) is that ROMP polymerizations can be conducted in a highly controlled way employing "living" catalysts such as the Grubbs family of catalysts. Such "living" chain-growth polymerizations enable unique control over molecular structure and composition, chain-length and end groups. More particularly, it is possible to prepare well-defined di-, tri- and multiblock copolymers, as well as gradient compositional copolymers. See for example, Furstner, A. Angew. Chem. , Int. Ed. 2000, 39, 301 3 ; T. M. Trnka, T. M ; Grubbs, R. H. Acc. Chem. Res. 2001 , 34, 1 8; each of which is respectively incorporated herein by reference for their teachings regarding methods and catalysts for ROMP polymerizations.

[00086] Example 7 and the drawing below illustrates the synthesis of such a norbomenyl diblock copolymer, XH-I-68a, via sequential ROMP polymerization of one of the norbomenyl monomers shown above, fol lowed by addition of the second norbomenyl monomer shown above.

[00087] As further described below, such norbomenyl diblock copolymers can be used as "phase compatibi lizers" to prevent, modify / control, and stabi lize the norbomenyl polymer blend compositions of the invention against undesirable phase separations.

Polymer Blend Compositions Comprising Blends of Norbornenyl-Hole Transporting and Norbornenyl-Electron Transporting Homopolymers

[00088] In many aspects, the inventions described herein relate to a composition comprising a blend of

a. at least one first norbomeny l polymer or copolymer comprising one or more norbomenyl subunits in the polymer backbone linked to at least one optional ly substituted arylam ine hole transporting side group, and

b. at least one additional norbomenyl polymer or copolymer comprising one or more norbomenyl subunits in the polymer backbone linked to at least one optionally substituted electron transporting side group. [00089] The linking groups, optionally substituted arylamine hole transporting side groups, and/or optional ly substituted electron transporting side groups (of the first norbornenyl polymer or copolymer or additional norbornenyl polymer or copolymer) can be any of the groups and/or combinations thereof described above.

[00090] The blend compositions comprise at least two components, including at least one first norbornenyl hole transporting polymer or copolymer and at least one add itional norbornenyl electron transporting polymer or copolymer as described above, but may and often do comprise other components. The blend compositions may be physical blends of the separate components, or blends of the materials in l iquid solution dissolved or suspended in an optional solvent, or be in the form of sol id phase m ixtures or solid solutions (preferably amorphous sol id phases or solid solutions). A lternatively, solid phases formed from such polymer or copolymer blends may be partial ly phase separated or partial ly crystal lized, but the two or more component materials or phases are preferably still in intimate contact on the nanometer and/or micrometer scales.

[00091 ] In many embodiments, the blend compositions are a single amorphous sol id phase, preferably with a glass transition temperature of at least 1 20°C. In many other embodiments, the blend compositions comprise a m ixture of at least two or more amorphous sol id phases, preferably wherein each amorphous sol id phase preferably has a glass temperature of at least 120°C.

[00092] In many embodiments, the blend compositions su itable for making OLED emissive layers comprise a luminescent guest emitter. Many such guest em itters are known to those of ordinary skill in the "OLED" art, and many of those known guest em itters can be used in the blend compositions described herein, and can be selected from non-polymeric small molecules, organic oligomers, and polymers or copolymers comprising emitter chromophores. In many em bodiments the guest em itter is at least somewhat soluble in common organic solvents, so as to make for easy preparation and application of the blend compositions by solution processes. It is preferred that the guest em itter remains highly d ispersed in the host polymer blend after deposition of the em ission layer.

[00093] In many embodiments the guest em itter is a metal complex wherein the metal is Re, Ru, Os, Rh, Ir, Pd, Pt, Cu or Au. Metal complexes comprising 3d row transition elements such as Re, Os, Ir, Pt, or Au are often employed because they can accept energy from both singlet and triplet excitons from the host, and aid the conversion of the singlets to triplets, and then phosphoresce from their triplet states. Various complexes of Ir and Pt are particularly well known as high ly efficient triplet guest em itters. Several such Ir complexes that are highly efficient em itters of green or blue light are described below..

[00094] The blend compositions of the invention can contain variable proportions of the first norbornenyl hole transporting polymer or copolymer as compared to the add itional norbornenyl electron transporting polymer or copolymer. Applicants have unexpected ly discovered that, especial ly in the case of blends of the first norbornenyl hole transporting polymer and additional norbornenyl electron transporting polymer or copolymer, that the proportions of the polymers can be varied over a wide range enabl ing to tune, optimize and stabilize the efficiency of the resulting OLED devices. See for example Examples 10-12 and correspond ing Figures 8-10 below. The tunabi lity is further increased by the high control over the molecular weight within a wide range: The number average degree of polymerization can be varied from about 3 to about 300. It is not required to use high molecular weights; low/moderate degrees of polymerization, from about 3 to 50, more preferably from about 3 to 30, are advantageous, both for ease of solubi l ity in common solvents and solid phase blend m ixing.

[00095] Wh i le the specific effects of such variations in the ratios of the polymers in the blends will of course vary with the specific identity of the polymers, devices and other components of the devices, and without wishing to be bound by theories, it is bel ieved that such variations in the ratios of the hole-transporting and electron transporting polymers or copolymers can help to benefic ial ly optim ize the balance of holes and electrons suppl ied to the luminescent emitters in the em ission layers of the OLEDs during operation. Preferably the weight ratio of the hole-transporting and electron transporting polymers or copolymers can be varied from about 1 : 5 to about 5 : 1 , or from about 3 : 1 to about 1 :3, or from about 2: 1 to about 1 :2, or from about 1 .5 : 1 to about 1 : 1 .5.

[00096] As already noted above, in some embodiments the blend compositions are a single amorphous sol id phase, while in other embodiments, the blend compositions comprise a m ixture of at least two or more amorphous sol id phases. The phase morphology of the blend compositions, especial ly when they are being employed to form em issive layers of OLED devices, can have an important effect on OLED performance, so it is highly desirable that the phase morphology of the blend compositions be controllable and stable.

[00097] In that regard, the norbomenyl polymers and copolymers uti l ized in the present inventions provide a unique and unexpected opportunity for potentially modifying or stabi l izing the phase morphology of the blend compositions, because of the ease of making norbomenyl block copolymers that can serve as phase stabilizers.

[00098] Accordingly, in some embodiments of the blend compositions of the invention, the blend compositions may comprise a block norbomenyl copolymer comprising at least a first block comprising one or more polymerized norbomenyl subunits, in the block copolymer backbone, that are l inked to side groups comprising at least one optionally substituted hole transporting group; and a second block comprising one or more polymerized norbomenyl subunits, in the block copolymer backbone, linked to side groups comprising at least one optional ly substituted electron transporting group. In such embodiments, it can be preferable that the norbomenyl subunits of the first norbomenyl- polymer and the first block of the block copolymer are the same, and that the subunits of the additional norbomenyl polymer and the second block of the block copolymer are the same.

[00099] In many embodiments of the blend compositions that do comprise such block norbomenyl copolymers, the first block of the block norbomenyl copolymer comprises a plurality of, or consists essentially of, norbomenyl subunits having the structure

wherein

a) L 1 is an organic l inking group,

b) R c comprises any of the Rc groups discussed above with respect to the first norbomenyl hole transporting polymers or copolymers.

[000100] In many embodiments of the blend compositions that do comprise such block norbomenyl copolymers, the block norbomenyl copolymer also comprises a block that comprises a plurality of, or consists essentially of norbornenyl subunits having the structure

wherein

L 2 is an organic linking group, and

R o can be any of the R o groups disclosed above in connection with the norbornenyl electron transporting polymers and copolymers.

[000101 ] In many embodiments, the block norbornenyl copolymers can be present at a concentration of from about 0. 1 to about 20 wt% of the com position, or from about 0. 1 to about 10 wt% of the composition.

[000102] Whi le not wishing to be bound by theories, it is thought that the phase stabilization that can be achieved by adding such norbornyl block copolymers to the blend compositions of the inventions may result from the ability of the two different copolymer blocks, one having norbornenyl hole transporting subunits, and another block having norbornenyl electron transporting subunits, to be physical ly, chemical ly, and thermodynamically compatible with the similar norbornenyl hole transporting subunits, and norbornenyl electron transporting subun its in the primary polymers or copolymers of the blend, so that they compatibilize the two primary norbornenyl polymers or copolymers against phase separation, so that the overal l polymer blend can be stabi lized as a single phase.

[000103] A lternatively, in embodiments wherein the two or more primary norbornenyl copolymers do desirably undergo at least some degree of phase segregation, the block copolymers may self-orient themselves at the interfaces of the separate phases, so as to stabilize, or alter or "tune" the degree of phase separation. Accordingly, unique and unexpected advantages can derive from the use of norbornenyl polymers, copolymers, and block copolymers, which al low the easy preparation of high ly compatible norbornenyl polymers, copolymers, and block copolymers.

OLEDs Comprising the Polymers and Copolymer Blends [000104] Some aspects of the present inventions relate to novel organic electronic devices, especially organic light emitting diodes (OLED) devices that comprise the various homopolymers and copolymers described herein as components of host blend compositions for making the emission layers of OLEDs. As further described below, many of the various compounds, homopolymers, copolymers are often readily soluble in common organic solvents or mixtures thereof and can be mixed with guest phosphorescent emitters, and the polymer blend solutions coated or wet-printed by various printing technologies onto appropriate substrates to form a smooth, defect-free emission layer of an OLED device.

[000105] In many embodiments, the OLED devices comprise an anode layer, a hole transporting layer, an emission layer, an electron transporting layer, and a cathode layer. Such devices are illustrated in the diagram below:

Cathode Layer

Electron Transporting Layer

Emission Layer

Hole Transporting Layer

- Anode Layer

- Glass

OLED Device

[000106] Accordingly, in many embodiments of the OLED devices disclosed herein, the OLEDs comprise the following layers:

an anode layer,

a hole transporting layer,

an emissive layer,

an electron transporting layer, and

a cathode layer.

[000107] In many embodiments of the OLED devices disclosed herein, the emissive layer comprises at least some of the blend compositions, especially when the norbornenyl hole transporting and norbomenyl electron transporting components are homopolymers, to form unexpectedly good hosts for guest emitters. [000108] Indium tin oxide (ITO) is a well known example of a suitable transparent semiconducting material for making the anode layers, and is often applied by vacuum deposition in a layer over an inert and transparent substrate such as glass.

Su itable ITO coated glass plates are available from Colorado Concept Coatings LLC, with a sheet resistivity of ~ l 5 or 20 Ω/sq, which were used as the substrate for the OLEDs fabrications described herein. The ITO coated substrates were patterned with kapton tape and etched in acid vapor ( 1 :3 by volume, HNO3: HCI) for 5 min at 60 °C. The substrates were cleaned in an u ltrason ic bath of detergent water, rinsed with deionized water, and then cleaned in sequential ultrasonic baths of deionized water, acetone, and isopropanol. Each u ltrasonic bath lasted for 20 minutes. Nitrogen was used to dry the substrates after each of the last three baths.

[0001 09] Many materials are potentially useful as hole transporting layers, includ ing monomeric or polymeric carbazole compounds, such as for example polyv inyl carbazole (PV , commercial ly available) which can be dissolved in a solvent such as toluene or chlorobenzene, and spun-coated onto the ITO substrates. PEDOT: PSS A14083, commercial ly available from Heraeus of Hanau Germany, is an aqueous dispersion of Poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate), structure shown below. PEDOT: PSS is typically spin coated (60s@ 1 500 rpm. acceleration 10,000) onto ITO coated glass substrates, in a 2 filled wet glove box, to form a hole-transporting layer with a thickness of about 40 nm. After spin-coating, a rectangular strip of the layer is removed at the edge of the substrate to expose ITO and ensure electrical contact to the anode; then the coated substrate is baked for 10 min at 140 °C on a hot plate. The PEDOT: PSS coated substrate is removed from the hot plate on ly until its temperature is down to 40

°C.

PDOT: PSS [0001 10] Poly-TPD-F (structure shown below, see Zhang, et al,. Synthesis 2002, 1201 and Domercq, et al., Chem. Mater. 2003, 75, 1491 , both of which are incorporated herein by reference in their entirety) is especially useful as a hole

transporting layer, because it is photo cross-linkable and can be used to produce photo- patterned hole transporting layers that are largely unaffected by solution processes for depositing the em issive layers comprising the norbornenyl polymer blend compositions

Poly-TPD-F

[0001 1 1 ] For the Poly-TPD-F hole-transport layer, 1 0 mg of Poly-TPD-F was typically dissolved in 1 ml of chloroform (purity of 99.8%; which was distilled and degassed over night). 35 nm thick films are then spin coated (60s@ 1 500 rpm, acceleration 1 0,000) onto the indium tin oxide (ITO) coated glass substrates, (pre-treated with an O2 plasma for 3 minutes prior to the deposition of the hole-transport material). Spin coating is carried out in a N 2 fil led wet glove box. After spin-coating, a rectangular strip of the layer is removed at the edge of the substrate to expose ITO and ensure electrical contact to the anode; then, the sample is transferred to the wet glove box ante-chamber and subjected to vacuum for 1 5 m inutes; then the sample is transferred back into the wet glove-box were it is baked for 1 5 m in at 75 °C on a hot plate, after which the hot plate is turned off. The sample is removed from the hot plate only after its temperature is down to 40 °C. Final ly the sample is exposed to 0.7 m W/cm 2 of UV il lum ination for 1 m inute to crosslink the TPD-F hole-transport layer.

[0001 12] The polymer blends described and claimed herein are typically employed as host materials for forming the emissive layers of OLEDs, by dissolving the individual polymers or blends thereof in common organic solvents such as toluene, chlorobenzene, and the l ike, and likewise containing soluble polymeric or non-polymeric guest emitters, which are most typically complexes of Iridium, Platinum, and other 3d row transition metals, see for example US 2006/0127696, or WO 2009/026235, the teachings of both of which are hereby incorporated by reference herein . Well-known blue emitters commonly used as guest emitters in OLED devices include FIrpic (Y. Kawamura et al. Appl. Phys. Lett.2005, 86, 071104/1), FIr 6 (T. Sajoto et al. Inorg. Chem.2005, 44, 7992- 8003) and lr(ppz) 3 (C. H. Yang et al. Angew. Chem. Int. Ed. 2007, 46, 2418-2421). Commonly used green emitters include Ir(ppy)3 (Y. Kawamura et al. Appl. Phys. Lett. 2005, 86, 071104/1), Ir(pppy) 3 (US 2006/127696), and lr(mppy) 3 (H. Wu et al. Adv. Mater.

Ir(ppy) 3 , Ir(ppy)3 FIrpic

[000113] Many organic materials are suitable as electron transporting and/or hole blocking materials, such as a variety of substituted phenanthrolines, such as bathocuproine (BCP = 2,9-dimethyl-4,7-diphenyl-l,10-phenanthroline) and BPhen (4,7- diphenyl-l,IO-phenanthroline), quinolates such as Alq3 and BAlq, imidazoles such as TPBI (2,2',2"-(l,3,5-phenylene)tris(l-phenyl-lH-benzimidazole), or various phenyl- pyridyls, such as "B3PyPB" (3,5,3",5"-tetra-3-pyridyl-[l ,Γ;3',1 "]terphenyl)„ which can be readily applied ues.

B3PyPB TPBI

[0001 14] Many materials can be suitable as cathode layers, one example being a combination of lithium fluoride (LiF) as an electron injecting material coated with a vacuum deposited layer of Aluminum.

Electroluminescent Properties of the OLED Devices

[0001 15] Examples 9, 10, 1 1 , and 12 below illustrate the unexpectedly good performance of OLEDs comprising the norbornenyl polymer blend compositions of the invention when used with green phosphorescent emitters, in terms of a combination of reasonable turn-on voltages, very good brightness, and excellent External Quantum Efficiencies (EQE) and luminous efficiencies. It is notable that efficiencies were clearly significantly dependent on the ratios of the norbornenyl-carbazolyl homopolymer and the norbomenyl-oxadiazolyl homopolymer.

[0001 16] Examples 13 and 14 illustrate the suitability of the norbornenyl polymer blend compositions of the invention for use with blue emitters, such as Firpic, though a different hole transport material was used(PEDOT:PSS vs TPD-F in Examples 9- 12), and luminous efficiencies were significantly lower in the blue OLEDs actually made and tested.

[0001 17] Comparative device Examples 15-20 illustrate the significantly poorer results obtained from comparative tests of OLEDs comprising other structural types of polymers containing the same types of carbazole and oxadiazole groups.

[0001 1 8] Comparative Exampled 15 and 16 describe OLED devices employing an emissive layer comprising random norbornenyl copolymers (XH-I-41 or XH-I-53c) comprising norbornenyl-bisoxadizole subunits and norbornenyl-triscarbazole subunits, and the results of testing of that OLED. The EQEs obtained from the comparative devices are clearly significantly inferior to the OLED devices of the invention, see for example Example 12.

[0001 1 9] Comparative Example 1 7 describes an OLED device employing an em issive layer comprising a diblock norbornenyl copolymer (XH-I-68a)comprising norbornenyl-bisoxadizole subun its and norbornenyl-triscarbazole subunits, and the results of testing of that OLED. The EQEs obtained from the comparative device are clearly significantly inferior to the OLED devices of the invention, see for example Example 1 2.

[000120] Comparative Example 1 8 describes an OLED device employing an emissive layer comprising a random styrenic copolymer (YZ-IV-25) comprising norbornenyl-bisoxadizole subunits and norbornenyl-triscarbazole subunits, and the results of testing of that OLED. The EQEs obtained from the comparative device are clearly significantly inferior to the OLED devices of the invention, see for example Example 1 2.

[0001 21 ] Comparative Examples 19 and 20 describe OLED devices employing an emissive layer comprising random styrenic hompolymers comprising norbornenyl subunits in the polymer backbones that contained both oxadizole and carbazole groups within the same sidechains, and the results of testing of that OLED. The EQEs obtained from the comparative devices are clearly significantly inferior to the OLED devices of the invention, see for example Example 12.

[000122] The details of the complex physical interactions that combine to produce the results illustrated by the examples and comparative examples included herein are not yet well understood. Nevertheless, the OLED device Examples and Comparative Examples cited immediately above empirically support an assertion that the norbornenyl polymer blend compositions summarized above, described in detai l below, and/or claimed herein can be uti lized to prepare OLEDs with unexpectedly good electrical and em issive properties, as compared to the known prior art or obv ious variations thereof.

EXAMPLES

[000123] The various inventions described above are further illustrated by the following specific examples, which are not intended to be construed in any way as imposing l imitations upon the scope of the invention disclosures or claims attached herewith. On the contrary, it is to be clearly understood that resort may be had to various other embodiments, mod ifications, and equivalents thereof wh ich, after reading the description herein, may suggest themselves to one of ordinary skill in the art without departing from the scope of the inventions described herein.

[000124] General - A l l experiments with air- and moisture-sensitive intermediates and compounds were carried out under an inert atmosphere using standard Schlenk techniques. NMR spectra were recorded on either a 400 MHz Varian Mercury spectrometer or a 400 MHz Bruker AMX 400 and referenced to residual proton solvent. UV-vis absorption spectra were recorded on a Varian Cary 5E UV-vis-N IR spectrophotometer, wh i le solution and th in-fi lm PL spectra were recorded on a Fluorolog I I I ISA spectrofluorometer. Lifetime measurements were taken using a PTI mode l C-72 fluorescence laser spectrophotometer with a PTI GL-3300 nitrogen laser. Cyclic voltammograms were obtained on a computer controlled BAS 100B electrochem ical analyzer, and measurements were carried out under a nitrogen flow in deoxygenated DMF solutions of tetra-rc-butylammonium hexafluorophosphate (0.1 M). Glassy carbon was used as the working electrode, a Pt wire as the counter electrode, and an Ag wire anodized with AgCI as the pseudo-reference electrode. Potentials were referenced to the ferrocenium/ferrocene (FeCp2 +/0 ) couple by using ferrocene as an internal standard. Gel- permeation chromatography (GPC) analyses were carried out using a Waters 1 525 binary pump coupled to a Waters 2414 refractive index detector with methylene chloride as an eluent on American Polymer Standards 10 μπι particle size, linear m ixed bed packing columns. The flow rate used for all measurements was 1 m l/m in, and the GPCs were cal ibrated using poly(styrene) standards. Differential scanning calorimetry (DSC) data were collected using a Seiko model DSC 220C. Thermal gravimetric analysis (TGA) data were collected using a Seiko model TG DTA 320. Inductively coupled plasma-mass spectrometry (ICP-MS) for platinum and ruthenium was provided by Bodycote Testing Group. Ή-NMR and l 3 C-NMR spectra (300 MHz Ή NMR, 75 MHz l 3 C NMR) were obtained using a Varian Mercury Vx 300 spectrometer. A ll spectra are referenced to residual proton solvent. Abbreviations used include singlet (s), doublet (d), doublet of doublets (dd), triplet (t), triplet of doublets (td) and unresolved multiplet (m). Mass spectral analyses were provided by the Georgia Tech Mass Spectrometry Faci l ity. The onset of thermal degradation for the polymers was measured by thermal gravimetric analysis (TGA) using a Shimadzu TGA-50. UV/vis absorption measurements were taken on a Shimadzu UV-2401 PC recording spectrophotometer. Emission measurements were acquired using a Shimadzu RF-5301 PC spectrofluorophotometer. Lifetime measurements were taken using a PT1 model C-72 fluorescence laser spectrophotometer with a PTI GL- 3300 nitrogen laser. Elemental analyses for C, H, and N were performed using Perkin Elmer Series II CHNS/O Analyzer 2400. Elemental analyses for iridium were provided by Galbraith Laboratories.

[000125] Unless otherwise noted, cited reagents and solvents were purchased from well-known commercial sources (such as Sigma-Aldrich of Milwaukee Wisconsin or Acros Organics of Geel Belgium, and were used as received without further purification.

[000126] Example 1 - Synthesis of 9'-i5-((lS.2R.4S)-bicvclol2.2.11hept-5-

[000127] Triscarbazole ( 10.1 5 g, 20.4 mmol) and 2.5 equivalent of 5-(5- bromopentyl)-norbornene ( 10.0 mL, 50.3 mmol) were added into DMF ( 100 mL) under

N 2 . Then 2CO3 ( 13.99 g, 101 .2 mmol) were added into the reaction mixture. The reaction was heated to 100 °C for 60 hours. The reaction mixture was then cooled to room temperature and water (50 mL) was added into the system to precipitate a yellow solid.

The crude product was isolated by filtration and purified by recrystallization and silica gel column (CH 2 CI 2 ) to give a white solid ( 12.1 g, 90 %). Ή NMR (400 MHz, CDCI3): S 8.21

(s, br, 2H), 8.1 5 (d, J = 7.6 Hz, br, 4H), 7.65 (s, br, 4H), 7.38 (q, J = 8 Hz, 4H), 7.37 (s, br, 4H), 7.27 (dd, J, = 6.0 Hz, J 2 = 2.0 Hz, 2H), 7.25 (dd, J t = 6.0 Hz, J 2 = 2.0 Hz, 2H),

6.1 1 (dd, J/ = 5.6 Hz, J 2 = 2.8 Hz, 1 H), 5.91 (dd, J/ = 5.6 Hz, J 2 = 2.8 Hz, 1 H), 4.47 (t, J =

7.2 Hz, 2H), 2.75 (s, br, 2H), 2.06-1 .94 (m, 3H), 1 .85 (dd, J = 1 1 .2 Hz, J 2 = 4.0 Hz, 1 H),

1 .53-1 .06 (m, 8H), 0.49 (ddd, J, = 1 1 .2 Hz, J 2 = 4.0 Hz, J 3 = 2.8 Hz, 1 H). I 3 C { H}NMR ( 100 MHz, CDC ): δ 142.06, 140.39, 137.29, 132.52, 129.51 , 126.16, 126.05, 123.59,

123.31 , 120.48, 120.04, 1 19.82, 1 10.32, 109.94, 49.82, 45.66, 43.91 , 42.74, 38.97, 34.94, 32.68, 29.40, 28.74, 27.89. Anal. Calcd. for C 48 H 4 |N 3 : C, 87.37; H, 6.26; N, 6.37. Found:

C, 87.28; H, 6.30; N, 6.37. HRMS (EI) [M + ] calcd. for C 8rL,|N 3 : 659.3300. found:

659.3285.

[000128] Methods for the synthesis of many similar polymerizable norbornenyl monomers linked to carbazole groups, and norbornenyl homopolymers derived therefrom, were disclosed in WO 2009/080799, hereby incorporated herein by reference in its

entirity.

[000129] Example 2 - Synthesis of Polymerizable Norbornenyl-Oxadiazole Monomer; 2-(3-((5-(bicyclo|2.2.11hept-5-en-2-yl)pen v))oxy)phenyl) -5-(3-(S-(4-(tert- buryl)phenyl)-l,3,4-oxadiazol-2-vhphenyl>-l,3,4-oxadiazol e

2-(5-((5-(bicyclo[2.2.1 ]hept-5-en-2-yl)pentyl)oxy)phenyl)-5-(3-(5-(4-(/eri- butyl)phenyl)-1 ,3,4-oxadiazol-2-yl)phenyl)-1 ,3,4-oxadiazole

[000130] The synthesis of the 3-(5-(3-(5-(4-(tert-butyl)phenyl)-l ,3,4- oxadiazol-2-yl)phenyl)- l ,3,4-oxadiazol-2-yl)phenol bis-oxadiazole starting material

shown above, as well as the synthesis of a variety of additional polymerizable

norbomenyl-linked oxadiazole monomers, and homopolymers derived therefrom, were described in WO 2009/080797, hereby incorporated herein by reference in its entirety.

[000131 ] To a solution of 3-(5-(3-(5-(4-tert-Butylphenyl)- 1 ,3,4-oxadiazol-2- yl)phenyl)- l ,3,4-oxadiazol-2-yl)phenol (8.0 g, 18.24 mmol) and 5-

(bromomethyl)bicycle[2,2, l ]hept-2-ene (5.0 g, 20.56 mmol) in DMF ( 100.0 ml) was

added 2CO3 ( 10.0 g, 72.36 mmol) at room temperature under stirring. The reaction was carried out at 60°C for 18 h. After cooling, water (500.0 ml) was added. White solid

product was obtained by filtration. After dry, the crude product was purified by silica gel column chromatography using dichloromethane/ethyl acetate (9 : I ) as eluent. After removal of solvents, the product was purified by recrystallization from

dichloromethane/methanol. White solid product was obtained by filtration. After vacuum dry, the product as a white solid in 7.1 g (64.5%) was obtained.

[000132] Ή NMR (400 MHz, CDC! 3 ) δ: 8.83 (m, 1 H), 8.30 (m, 2 Hz), 8.08 (d, J = 8.4 Hz, 2 H), 7.70 -7.65 (m, 3 H), 7.56 (d, J = 8.4 Hz, 2 H), 7.42 (t, J = 8.0 Hz, 1 H), 7.06 (m, 1 H), 6.08 (q, J = 3.2 Hz, C=C-H, 0.85 H, endo), 6.06 (q, J= 3.2 Hz, 0.15 H, exo), 5.98 (q, J = 3.2 Hz, 0.15 H, exo), 5.89 (q, J= 3.2 Hz, 0.85 H, endo), 4.03 (t, J = 6.8 Hz, 2 H, OCH 2 ), 2.72 (m, br, 1.7 H), 2.49 (s, br, 0.3 H), 1.96 (m, 1 H), 1.81 (m, 2.5 H), 1.46-1.03 (m, 7.5 H), 0.47 (m, 1 H) ppm. I3 CNMR(100 MHz, CDC1 3 ) δ: 165.12, 165.01, 163.60, 163.34, 159.56, 155.65, 136.91, 132.33, 130.21, 129.96, 129.71, 129.66, 126.90, 126.10, 125.13, 124.98, 124.91, 124.61, 120.74, 119.23, 118.79, 112.31,68.34, 49.52, 45.37, 42.48, 38.65, 35.10, 34.65, 32.38, 31.09, 29.18, 28.38, 26.24 ppm. MS-EI (m/z): [M + ] Calcd for C^oNaC , 600.3, 601.3, 602.3. found 600.3, 601.3, 602.3. Anal. Calcd for C 38 H4oN 4 ' o 3 : C, 75.97; H, 6.71 ; N, 9.33. Found: C, 75.96; H, 6.76; N, 9.24.

[000133] Example 3 - Synthesis of A Norbornenyl Homopolymer

Comprising Linked Bis-oxadiazole Moieties- Poly(2-(3-((5-((lS,2R,4S)- bicyclo|2.2.11 hept-5-en-2-yl)pentvDoxy)phenyl)-5-(3-(5-(4-(tert-putyl)phen yl)- 1,3,4- oxadiazol-2-yl)phenyl)-l,3,4-oxadiazole); XH-I-98a

XH-l-98a

Poly(2-CM(S-«1S.2R.4S)-bicycb[2.21]hept- 5^ιν2^Ι)ρβηΙγΙ)οχγ )-5-<3-(Ε-(4-((β/·Ι- bu1yl)phenyl)-1,3,4-oxadiazol-2-yl)phenyl)- 1,3,4-oxadiazole) [0001 34] 2-(3-((5-(bicyclo[2.2. 1 ]hept-5-en-2-yl)pentyl)oxy)phenyl) -5-(3-(5- (4-(tert-butyl)phenyl)- l ,3,4-oxadiazol-2-yl)phenyl)- l ,3,4-oxad iazole (2.5406 g, 4.23 mmol) and the 1 st generation Grubbs catalyst (0.0034 g, 0.00 1 mmol) were weighed and sealed in a glove box, respectively. Under N?, the monomer and the catalyst were dissolved into 1 5 mL and 5 mL of anaerobic and anhydrous CH2CI2. Then the 5 mL

CH2CI2 solution of the catalyst was added dropwise into the CH2CI2 solution of the monomer. The polymerization proceeded at room temperature and the Schlenk tube was covered by A luminum foi ls. After 40 m in, when the reaction appeared complete by TLC, the polymerization was quenched with vinyl ethyl ether ( 1 .0 mL). Then the reaction m ixture was added dropwise to highly stirring acetone (200 m L) to precipitate out the polymer. The crude product was dried and purified by redissolv ing and reprecipitating process in acetone then methanol for three times to give an off-white solid (2.324 g, 92 %). Ή NMR (400 MHz, CDCI3): ^ 8.69 (m, br, I H), 8. 1 9 (m, br, 2H), 8.00 (m, br, 2H), 7.59 (m, br, 2H), 7.50 (m, br, 2H), 7.33 (m, br, 1 H), 6.98 (m, br, I H), 5.26 (m, br, 2H), 3.96 (m, br, 2H), 2.91 - 1 .73 (m, br, 6H), 1 .59-0.86 (m, br, 1 8H). Anal. Calcd. for

C38H40N4O3: C, 75.97; H, 6.71 ; N, 9.33 ; Found: C, 75.91 ; H, 6.69; N, 9.34. GPC: Mn (kDa): 36; Mw (kDa): 58; PD1: 1 .6.

[000135] The absorption and fluorescent em ission spectra of XH-l-98a in dichloromethane are shown in Figure 1. Absorption maxima were observed at 289 nm and 227 nm, and a fluorescent em ission maximum was observed at 366 nm.

Thermogravimetric Analysis showed good thermal stability, with 5% mass lost at 397 °C, and differential scanning calorimetry showed peak attributable to a glass transition temperature at 1 20 °C.

[0001 36] Example 4 - Synthesis of A Norbornenyl Homopolymer

Comprising A Lin ked Triscarbazole Moiety- Polv(9'-(5-((lS,2R,4S)- bicvclo[2.2.1 l hept-5-en-2-vnpenrvn-9'H-9.3':6'.9"-tercarbazole>; XH-I-98b

alyst XH-h98b

Poly-(9'-(5-((1 S,2R,4S)-bicydo[2.2.1 ]hept- 5- en-2-yl)pentyl)-9'H-9,3':6',9"-tercarbazole)

[000137] 9'-(5-(( 1 S,2R,4S)-bicyclo[2.2.1 ]hept-5-en-2-y l)pentyl)-9'H-9,3':6\9"- tercarbazole (2.5401 g, 3.85 mmol) and the 1 st generation Grubbs catalyst (0.0029 g, 0.0035 mmol) were weighed and sealed in a glove box, respectively. Under N2, the monomer and the catalyst were dissolved into 15 mL and 5 mL of anaerobic and anhydrous CH2CI2. Then the 5 mL CH2CI2 solution of the catalyst was added dropwise into the CH2CI2 solution of the monomer. The polymerization proceeded at room temperature overnight. When the reaction appeared complete by TLC, quenched the polymerization with vinyl ethyl ether ( 1.0 mL). Then the reaction mixture was added dropwise to highly stirring acetone (200 mL) to precipitate out the polymer. The crude product was dried and purified by redissolving and reprecipitating process in acetone then methanol for three times to give an off-white solid (2.258 g, 89 %).

[000138] Ή NMR (400 MHz, CDCI 3 ): i(ppm): 8.08 (m, br, 2H), 8.02 (m, br, 4H), 7.45 (m, br, 4H), 7.24 (m, br, 8H), 7.14 (m, br, 4H), 5.1 1 (m, br, 2H), 4.16 (m, br, 2H), 2.70-1.75 (m, br, 7H), 1 .24-0.93 (m, br, 8H). Anal. Calcd. for C, 87.37; H, 6.26; N, 6.37. Found: C, 86.84; H, 6.23; N, 6.38. GPC: Mn (kDa): 23; Mw (kDa): 35; PDI: 1.5.

[000139] The absorption and fluorescent emission spectra of XH-I-98b in dichloromethane are shown in Figure 2. Absorption maxima were observed at 342 nm, 294 nm, 264 nm, and 239 nm, and fluorescent emission maxima was observed at 408 and 391 nm. Thermogravimetric Analysis showed good thermal stability, with 5% mass lost at 445 °C, and differential scanning calorimetry showed peak attributable to a glass transition temperature at 206 °C. [000140] Example 5 - Synthesis of A Random Norbornenyl Copolymer Comprising 1 :1 BisOxadiazole and Triscarbazole Moieties; XH-I-41

[000141 ] The norbornene-triscarbazole monomers, 9'-(5-((l S,2R,4S)- bicyclo[2.2.1 ]hept-5-en-2-yl)pentyl)-9'H-9,3':6',9"-tercarbazole (0.4956 g, 0.752 mmol) and norbornene-bisoxadiazole monomer 2-(3-((5-(bicyclo[2.2.1 ]hept-5-en-2- yl)pentyl)oxy)phenyl) -5-(3-(5-(4-(tert-butyl)phenyl)-l ,3,4-oxadiazol-2-yl)phenyl)- l ,3,4- oxadiazole (0.4549 g, 0.757 mmol), and the 1 st generation Grubbs catalyst (0.0062 g, 0.00753 mmol) were weighed and sealed in two separate Schlenk tubes in a glove box, respectively. Under N 2 , the monomers and the catalyst were dissolved into 8 mL and 4mL of anaerobic and anhydrous CH 2 CI 2 . Then the 4 mL CH 2 CI 2 solution of the catalyst was added dropwise into the CH 2 CI 2 solution of the monomers. The polymerization proceeded at room temperature for 4 hours. When the reaction appeared complete by TLC, quenched the polymerization with vinyl ethyl ether (0.5 mL). Then the reaction mixture was added dropwise to highly stirring CH 3 OH (200 mL) to precipitate out the polymer. The crude product was dried and purified by redissolving and reprecipitating process three times to give a off-white solid (XH-I-41 , 0.775 g, 82 %).

[000142] ' H MR (400 MHz, CDCI 3 ): δ 8.69 (m, br, 1 H), 8.12 (m, br, 4H), 8.03 (m, br, 6H), 7.50 (m, br, 9H), 7.27 (m, br, 8H), 7.1 5 (m, br, 5H), 6.98 (m, br, 1 H), 5.18 (m, br, 4H), 4.31 (m, br, 2H), 3.89 (m, br, 2H), 2.83-1.53 (m, br, 14H), 1.48-1.04 (m, br, 25H). Anal. Calcd. for CgeHgiNvC : C, 81 .94; H, 6.48; N, 7.78. Found: C, 81 .94; H, 6.29; N, 7.67. GPC: Mn (kDa): 47; Mw (kDa): 74; PDI: 1.6. [000143] The absorption and fluorescent emission spectra of XH-I-41 in dichloromethane are shown in Figure 3. Absorption maxima were observed at 343, 294, and 238 nm, and fluorescent emission maxima was observed at 475, 407, and 390 nm. Thermogravimetric Analysis showed good thermal stability, with 5% mass lost at 423 °C, and differential scanning calorimetry showed peak attributable to a glass transition temperature at 1 54 °C.

[000144] Example 6 - Synthesis of A Random Norbornenyl Copolymer

[000145] The norbornene-triscarbazole monomers,-9'-(5-(( l S,2R,4S)- bicyclo[2.2.1 ]hept-5-en-2-yl)penryl)-9'H-9,3':6',9"-tercarbazole (0.2995 g, 0.454 mmol) and norbomene-bisoxadiazole monomer 2-(3-((5-(bicyclo[2.2.1 ]hept-5-en-2- yl)pentyl)oxy)pheny I) -5-(3-(5-(4-(tert-butyl)pheny I)- 1 ,3,4-oxadiazol-2-y l)pheny 1)- 1 ,3,4- oxadiazole (0.4134 g, 0.688 mmol), and the 1 st generation Grubbs catalyst (0.0036 g, 0.0043 mmol) were weighed and sealed in two separate Schlenk tubes in a glove box, respectively. Under :, the monomers and the catalyst were dissolved into 7 mL and 3 mL of anaerobic and anhydrous CHiCh. Then the 3 mL ChLCL solution of the catalyst was added dropwise into the CH?Ch solution of the monomers. The polymerization proceeded at room temperature and the Schlenk tube was covered by Aluminum foils. After 6 hours, when the reaction appeared complete by TLC, quenched the polymerization with vinyl ethyl ether (0.5 mL). Then the reaction mixture was added dropwise to highly stirring acetone (200 mL) to precipitate out the polymer. The crude product was dried and purified by redissolving and reprecipitating process for three times in acetone then methanol to give a off-white solid (XH-I-53c, 0.551 g, 77%).

[000146] Ή NMR (300 MHz, CDCI3): δ 8.69 (m, br, 1 ,5H), 8.09 (m, br, 10.5H), 7.53 (m, br, 12H), 7.28 (m, br, 8H), 7.18 (m, br, 6H), 6.98 (m, br, 2H), 5.25 (m, br, 5H), 4.37 (m, br, 2H), 3.92 (m, br, 3H), 2.87-1.73 (m, br, 1 5H), 1.32-0.46 (m, br, 35H). Anal. Calcd. for C 105H101N9O4 . 5: C, 80.78; H, 6.53; N, 8.08. Found: C, 80.05; H, 6.52; N, 8.06. GPC: Mn (kDa): 47; Mw (kDa): 78; PDI: 1.6.

[000147] The absorption and fluorescent emission spectra of XH-I-41 in dichloromethane are shown in Figure 4. Absorption maxima were observed at 343, 294, 287, and 238 nm, and fluorescent emission maxima was observed at 476, 390, 366, and 356 nm. Thermogravimetric Analysis showed good thermal stability, with 5% mass lost at 406 °C, and differential scanning calorimetry showed peak attributable to a glass transition temperature at 146 °C.

[000148] Example 7 - Synthesis of A Diblock Norbornenyl Copolymer Comprising 1 : 1 BisOxadiazole and Triscarbazole Moieties; XH-I-68a

[000149] The norbornene-triscarbazole monomers, 9'-(5-(( 1 S,2R,4S)- bicyclo[2.2. 1 ]hept-5-en-2-yl)pentyl)-9'H-9,3':6',9"-tercarbazole (0.3055 g, 0.463 mmol) and norbornene-bisoxadiazole monomer 2-(3-((5-(bicycIo[2.2. 1 ]hept-5-en-2- yl)pentyl)oxy)phenyl) -5-(3-(5-(4-(tert-butyl)phenyl)- l ,3,4-oxadiazol-2-yl)phenyl)- l ,3,4- oxadiazole (0.2726 g, 0.454 mmol), and the 1 st generation Grubbs catalyst (0.0035 g, 0.0042 mmol) were weighed and sealed in three separate Sch lenk tubes in a glove box, respectively. Under N 2 , the monomer YZ-lII-267a and the catalyst were dissolved into 4 m L and 2 m L of anaerobic and anhydrous CH2CI2. Then the 2 mL CH2CI2 solution of the catalyst was added dropwise into the 4 m L CH2CI2 solution of the first monomer YZ- I II- 267a. After the Schlenk tube was covered by Alum inum foi ls, the polymerization proceeded at room temperature for 30 m in. When the reaction appeared complete by TLC, transferred 4 mL of the reaction m ixture into the second monomer XH-I-27a. Sti l l cover the reaction m ixture with aluminum foils and let it stir for another 30 m in. The polymerization was quenched with vinyl ethyl ether (0.2 mL) after TLC confirmed the reaction was complete. Then the reaction mixture was added dropwise to highly stirring acetone (200 mL) to precipitate out the polymer. The crude product was dried and purified by redissolv ing and reprecipitating process for three times in acetone then methanol to give an off-white sol id (XH-I-68a, 0.454 g, 79 %). [0001 50] ' H NMR (400 MHz, CDCl 3 ): <? 8.69 (m, br, 1 H), 8. 19-8.01 (m, br, \ \ H), 7.60-7.24 (m, br, 1 3H), 7. 1 3-6.98 (m, br, 9H), 5.27 (m, br, 2H), 5. 1 1 (m, br, 2H), 4. 14 (m, br, 2H), 3.95 (m, br, 2H), 2.88-2. 1 5 (m, br, 5H), 1 .82- 1 .75 (m, br, 9H),

1 .40-0.88 (m, br, 25H). Anal. Calcd. for C86H 8 | 7 0 3 : C, 81 .94; H, 6.48; N, 7.78. Found: C, 82.20; H, 6.43 ; N, 7.67. GPC: Mn (kDa):38; w (kDa): 62; PD1 : 1 .6.

[0001 5 1 ] The absorption and fluorescent em ission spectra of XH-l-68a in dichloromethane are shown in Figure 5. Absorption maxima were observed at 342, 294, 264, and 238 nm, and fluorescent em ission maxima were observed at 389 and 366 nm nm. Thermogravimetric Analysis showed good thermal stability, with 5% mass lost at 410 °C, and d ifferential scanning calorimetry showed peak attributable to a glass transition temperature at 144 °C.

[0001 52] Example 8 - A Physical Blend of A Norborncnyl-Bisoxadiazole Homopolymer XH-I-98a with A Norbornenyl-Triscarbazole Homopolymer XH-l-98b : XH-I-69a

[0001 53] Samples of XH-I-98a and XH-I-98b in a 1 : 1 ratio were physically blended to form sample XH-I-69a.

[0001 54] The absorption and fluorescent emission spectra of XH-I-69a dissolved in dichloromethane are shown in Figure 6. Absorption maxima were observed at 342, 294, 286, and 238 nm, and fluorescent emission maxima were observed at 382 and 366 nm. Thermogravimetric Analysis showed good thermal stability, with 5% mass lost at 406 °C, and differential scanning calorimetry showed peak attributable to a glass transition temperature at 1 36 °C.

[0001 55] Example 9 - An OLED Device Employing an Emissive Layer Comprising A 1 : 1 Blend of A Norbornenyl-Bisoxadiazole Homopolymer XH-I-98a with A Norbornenyl-Triscarbazole Homopolymer XH-I-98b As Host In the Emissive Layer (6% Irfppy Emitter)

[0001 56]The fol lowing describes the construction and electronic testing of an OLED device comprising an em issive layer comprising a 1 : 1 (wt%) blend of a norbornenyl-bisoxadiazole homopolymer XH-l-98a (see synthesis Example 3) with a norbornenyl-triscarbazole homopolymer XH- l-98b (see synthesis Example 4), as Host in the OLED em issive layer. A schematic of the structure of the OLED device and graphs of the resu lts of the electronic testing are shown in Figures 7a, 7b, and 7c. [0001 57]Indium tin oxide (ITO)-coated glass (Colorado Concept Coatings LLC) with a sheet resistivity of ~1 5 Ω/sq was used as the substrate for the OLEDs fabrication. The ITO substrates were patterned with kapton tape and etched in acid vapor ( 1 :3 by volume, ITNO3: HCI) for 5 min at 60 °C. The substrates were cleaned in an ultrasonic bath of detergent water, rinsed with deionized water, and then cleaned in sequential ultrasonic baths of deionized water, acetone, and isopropanol. Each ultrasonic bath lasted for 20 m inutes. Nitrogen was used to dry the substrates after each of the last three baths. This same procedure was used to prepare the ITO coated substrates for all the subsequent examples below.

[0001 58]For the Poly-TPD-F hole-transport layer, 1 0 mg of Poly-TPD-F were dissolved in 1 ml of chloroform (with purity of 99.8%, as disti lled and degassed over night). 35 nm thick films were then spin coated (60s@ 1 500 rpm, acceleration

10,000rpm/s) onto the indium tin oxide (ITO) coated glass substrates, treated with an O2 plasma for 3 minutes prior to the deposition of the hole-transport material. Spin coating was carried out in a N? fi lled wet glove box. After spin-coating, a rectangular strip of the layer was removed at the edge of the substrate to expose ITO and ensure electrical contact to the anode; then, the sample was transferred to the wet glove box ante-chamber and subjected to vacuum for 1 5 m inutes; then the sample was transferred back into the wet glove-box were it was baked for 1 5 m in at 75 °C on a hot plate, after which the hot plate was turned off. The sample was removed from the hot plate only unti l its temperature was down to 40 °C. Finally the sample was exposed to 0.7 mW/cm 2 of UV il lumination for 1 m inute to crosslink the hole-transport layer.

[0001 59]For the em issive layer, 6 wt.% of Ir(ppy)3 was m ixed with a blend of XH- I-98a and XH-I-98b, at a 1 : 1 weight ratio, and all materials dissolved in 1 ml of chlorobenzene ( purity of 99.8%; distil led and degassed over night). 40-50 nm th ick fi lms were then spin coated (60s@ 1000 rpm, acceleration 1 0,000 rpm/s) onto the UV crossl inked poly-TPD-F layer. After spin-coating, the samples were baked at 75 °C for 1 5 m inutes. Chlorobenzene was then used to remove the emissive layer in the area not covered by poly-TPD-F, exposing the ITO substrate to provide electrical contact to the anode. The samples were then transferred, under a N 2 atmosphere, into an SPECTROS from Kurt J. Lesker thermal deposition system directly connected to the wet-glove box. [000160]For the hole-blocking and electron transport layer, a 40 nm thick BCP layer was vacuum deposited at a pressure below 2x 10 "7 Torr and at rates of 0.4 A/s, respectively. Then, a 2.4 nm of l ithium fluoride (LiF), as an electron-injection layer, and a 200 nm-thick alum inum cathode were vacuum deposited through a shadow mask at a pressure below 3 * 1 0 "7 Torr and at rates of 0. 1 5 A/s and 2 A/s, respectively. The shadow mask used for the evaporation of the metal electrodes yield five devices with an area of roughly 0. 1 cm 2 per substrate.

[000161 ]The dev ice testing was done, immediately-after the deposition of the metal cathode, in an inert atmosphere and without exposing the devices to air.

Luminance-current-voltage (L-I- V) characteristics of the devices were measured using a Keithley 2400 source meter for current-voltage measurements inside a nitrogen-fi lled glovebox with 0 2 and H2O levels < 20 and < 1 ppm, respectively., The current-voltage measurements for all the subsequent OLED examples were carried out with the same instruments and via the same procedure for all the OLED examples below.

[000162] As can be seen from Figure 7c, the OLEDs emplo ing the 1 : 1 polymer blends as hosts for a green guest emitter showed reasonable offset voltages of sl ightly over 8 volts, were quite bright with peak luminance greater than 10 3 cd/m 2 , and peak external quantum efficiencies above 16%.

[0001 63] Example 10 - An OLED Device Employing an Emissive Layer Comprising A 1 : 1 Blend of A Norbornenyl-Bisoxadiazole Homopolymer XH-I-98a with A Norbornenyl-Triscarbazole Homopolymer XH-I-98b As Host In the Emissive Layer (12% Ir(ppyh Emitter)

[000164] The same procedure as detailed in Example 9 was used to prepare an OLED, except that 1 2% Ir(ppy)3 was employed in the em issive layer. A schematic of the structure of the OLED device and graphs of the results of the electronic testing are shown in Figures 8a, 8b, and 8c.

[0001 65] As can be seen from Figure 8c, the OLEDs employing the 1 : 1 polymer blends as hosts for 1 2% of a green guest emitter showed reasonable offset voltages of sl ightly over 7 volts, were quite bright with peak lum inance greater than 10 3 cd/m 2 , and peak external quantum efficiencies up to about 1 0%.

[000166] Example 11 - An OLED Device Employing an Emissive Layer Comprising A 1.5: 1 Blend of A Norbornenyl-Bisoxadiazole Homopolymer XH-I-98a with A Norbornenyl-Triscarbazole Homopolymer XH-I-98b As Host In the Emissive Layer (6% Ir(ppy)i Emitter)

[000167] The same procedure as detailed in Example 9 was used to prepare an OLED, except that the wt ratio of Norbornenyl-Bisoxadiazole Homopolymer XH- I-98a to Norbornenyl-Triscarbazole Homopolymer XH-I-98b was changed to 1 .5 : 1 (6% Ir(ppy)3 was employed in the emissive layer). A schematic of the structure of the OLED device and graphs of the results of the electronic testing are shown in Figures 9a, 9b, and 9c.

[0001 68] As can be seen from Figure 9c, the OLEDs employing the 1 .5 : 1 polymer blends as hosts for 6% of a green guest emitter showed reasonable offset voltages of sl ightly over 7 volts, were quite bright with peak lum inance wel l over 1 0 3 cd/m 2 , and peak external quantum efficienc ies up to over 16%.

[0001 69] Example 12 - An OLED Device Employing an Emissive Layer Comprising A 1 : 1.5 Blend of A Norbornenyl-Bisoxadiazole Homopolymer XH-I-98a with A Norbornenyl-Triscarbazole Homopolymer XH-I-98b As Host In the Emissive Layer (6% Ir(pppy Emitter)

[0001 70] The same procedure as detailed in Example 9 was used to prepare an OLED, except that the wt ratio of Norbornenyl-Bisoxadiazole Homopolymer XH-I-98a to Norbornenyl-Triscarbazole Homopolymer XH-I-98b was changed to 1 : 1 .5, and 6% of a slightly different but well known green emitter, lr(pppy)3 (structure shown below) was employed in the em issive layer. A schematic of the structure of the OLED device and graphs of the results of the electronic testing are shown in Figures 10a, 10b, and 10c.

[0001 71 ] As can be seen from Figure 10c, the OLEDs employing the 1 : 1 .5 polymer blends as hosts for 6% of a green guest em itter showed reasonable offset voltages of about 6 volts, were very bright with peak lum inance wel l over 10 3 cd/m 2 , and peak external quantum efficiencies up to 28%. At 100 cd/m 2 , the EQE was 21 .0%, and lum inescent efficiency was 7 1 cd/A; and at 1000 cd/m 2 , the EQE was 14.5%, and lum inescent efficiency was 49 cd/A.

[0001 72] Example 13 - An OLED Device Employing an Emissive Layer Comprising A 1 : 1.5 Blend of A Norbornenyl-Bisoxadiazole Homopolymer XH-l-98a with A Norbornenyl-Triscarbazole Homopolymer XH-I-98b As Host In the Emissive Layer (6% Firpic Blue Emitter, PDOT:PSS As Hole Carrying Layer) [0001 73] A sim ilar procedure as detailed in Example 9 was used to prepare an OLED, using a 1 : 1 .5 wt ratio of Norbornenyl-Bisoxadiazole Homopolymer XH-I-98a to Norbornenyl-Triscarbazole Homopolymer XH-I-98b. but (6% of Firpic blue emitter was employed in the em issive layer, and the water soluble and solution processable material PEDOT:PSS was used as the hole carrying layer.

[0001 74] For the hole transport layer, a 40 nm thick PEDOT: PSS A I4083 layer was spin coated from the commercial ly available emu lsion (60s@ l 500 rpm, acceleration 1 0,000 rpm/s) onto 1TO coated glass substrates, in a N 2 fil led wet glove box. After spin-coating, a rectangular strip of the PEDOT;PSS layer was removed at the edge of the substrate to expose ITO and ensure electrical contact to the anode; then the PEDOT:PSS coated substrate was baked for 10 min at 140 °C on a hot plate. The sample was removed from the hot plate only until its temperature was down to 40 °C. The addition of the emissive layer, electron carrying layer, and cathode layers were then carried out as previously described above.

[0001 75] A schematic of the structure of the OLED device and graphs of the results of the electronic testing are shown in Figures 1 1a, l i b, and 11c.

[0001 76] As can be seen from Figure 1 lc, the OLEDs emplo ing the 1 : 1 .5 polymer blends as hosts for 6% of the blue guest emitter Firpic, and PEDOT: PSS hole carrying layers showed reasonable offset voltages of 7-8 volts, and were reasonably bright with peak luminance well over 10 3 cd/m 2 , and but the observed peak external quantum effic iencies were only about 2%.

[000177] Example 14 - An OLED Device Employing an Emissive Layer Comprising A 1 : 1.5 Blend of A Norbornenyl-Bisoxadiazole Homopolymer XH-l-98a with A Norbornenyl-Triscarbazole Homopolymer XH-I-98b As Host In the Emissive Layer ( 12% Firpic Blue Emitter, PDOT:PSS As Hole Carrying Layer. )

[0001 78] A similar procedure as detailed in Example 13 was used to prepare an OLED, using a 1 : 1 .5 wt ratio of Norbornenyl-Bisoxadiazole Homopolymer XH-I-98a to Norbornenyl-Triscarbazole Homopolymer XH-I-98b. but 1 2% of Firpic blue emitter was employed in the emissive layer, and the water soluble and solution processable material PEDOT:PSS was used as the hole carrying layer.

[0001 79] A schematic of the structure of the OLED device and graphs of the results of the electronic testing are shown in Figures 12a, 12b, and 12c. [0001 80] As can be seen from Figure 12c, the OLEDs employing the 1 : 1 .5 polymer blends as hosts for 1 2% of the blue guest em itter Firpic, and PEDOT:PSS hole carrying layers, showed reasonable offset voltages of about 8 volts, and were reasonably bright with peak lum inance well over 1 0 3 cd/m 2 , and but the observed peak external quantum efficiencies increased to about 4.5%, as compared to about 2% in Example 1 3.

[0001 8 1 ] Compa rative Example 15 - An PLED Device Employing an Emissive Layer Comprising A Random Copolymer of Norbornenyl-Bisoxadiazole Subunits With Norbornenyl-Triscarbazole Subunits, XH-I-41 As Host In the Emissive Layer (6% lr(ppyh Emitter)

[0001 82] A similar procedure as detailed in Example 9 was used to prepare an OLED, using a random copolymer of norbornenyl-bisoxadiazole subunits with norbornenyl-triscarbazole subunits, XH-I-41 , see Example 5, in the em issive layer.

[000183] For the emissive layer, 6 wt.% of Ir(ppy) 3 was mixed with XH-I- 1 and both materials dissolved in 1 ml of chlorobenzene ( purity of 99.8%; d istilled and degassed over night). 40-50 nm thick films were then spin coated (60s@ 1000 rpm, acceleration 10,000 rpm/s) onto the UV crosslinked poly-TPD-F layer. After spin-coating, the samples were baked at 75 °C for 1 5 m inutes. Chlorobenzene was then used to remove the em issive layer in the area not covered by poly-TPD-F, exposing the ITO substrate to provide electrical contact to the anode. The coated devices were then transferred, under a N 2 atmosphere, into an SPECTROS from Kurt J. Lesker thermal deposition system d irectly connected to the wet-glove box, for deposition of the electron transfer layer and cathode.

[0001 84] A schematic of the structure of the OLED device and graphs of the results of the electronic testing are shown in Figures 13a, 13b, and 13c.

[0001 85] As can be seen from Figure 13c, the OLEDs employing the random norbornenyl-oxadizole-carbazole as hosts showed reasonable offset voltages of about 8 volts, and were reasonably bright with peak luminance well over 1 0 3 cd/m 2 , and but the observed peak external quantum efficiencies started at a maximum of about 6%, which declined rapid ly with increasing voltage and current.

[0001 86] Comparative Example 16 - An OLED Device Employing an Emissive Layer Comprising A Random Copolymer of 3:2 Norbornenyl-Bisoxadiazole Subunits With Norbornenyl-Triscarbazole Subunits, XH-l-53c As Host In the Emissive Layer (6% Ir(ppy)¾ Emitter)

[0001 87] A sim ilar procedure as detailed in Example 9 was used to prepare an OLED, using a random copolymer of norbornenyl-bisoxadiazole subunits with norbornenyl-triscarbazole subunits in a 3 :2 ratio, XH-I-53c, see Example 6, in the emissive layer.

[0001 88] For the em issive layer, 6 wt.% of lr(ppy) 3 was m ixed with XH-I-53c and both materials dissolved in 1 m l of chlorobenzene (purity of 99.8%; d isti lled and degassed over night). 40-50 nm thick films were then spin coated (60s@ 1 000 rpm, acceleration 1 0,000 rpm/s) onto the UV crosslinked poly-TPD-F layer. After spin-coating, the samples were baked at 75 °C for 1 5 m inutes. Chlorobenzene was then used to remove the em issive layer in the area not covered by poly-TPD-F, exposing the ITO substrate to provide electrical contact to the anode. The coated devices were then transfened, under a N2 atmosphere, into an SPECTROS from Kurt J. Lesker thermal deposition system directly connected to the wet-glove box, for deposition of the electron transfer layer and cathode.

[0001 89] A schematic of the structure of the OLED device and graphs of the results of the electronic testing are shown in Figures 14a, 14b, and 14c.

[000190] As can be seen from Figure 14c, the OLEDs employing the random norbornenyl-oxadizole-carbazole as hosts showed reasonable offset voltages of about 8 volts, and were reasonably bright with peak luminance wel l over 1 0 3 cd/m 2 , and but the observed peak external quantum efficiencies started at a maximum of about 10%, which decl ined rapidly with increasing voltage and current.

[000191 ] Comparative Example 17 - An OLED Device Employing an Emissive Layer Comprising A Diblock Copolymer of 1 : 1 Norbornenyl-Bisoxadiazole Subunits With Norbornenyl-Triscarbazole Subunits, XH-I-68a As Host In the Emissive Layer (6% Ir(ppy)^ Emitter)

[000192] A sim ilar procedure as detailed in Example 9 was used to prepare an OLED, using a diblock copolymer of norbornenyl-bisoxadiazole subunits with norbornenyl-triscarbazole subunits in a 1 : 1 ratio, XH-I-68a, see Example 7, in the emissive layer. [000193] For the em issive layer, 6 wt.% of Ir(ppy) 3 was m ixed with XH-I-68a and both materials dissolved in 1 m l of chlorobenzene (purity of 99.8%; disti lled and degassed over night). 40-50 nm thick fi lms were then spin coated (60s@ 1 000 rpm, acceleration 10,000 rpm/s) onto the UV crosslinked poly-TPD-F layer. After spin-coating, the samples were baked at 75 °C for 1 5 minutes. Chlorobenzene was then used to remove the em issive layer in the area not covered by poly-TPD-F, exposing the ITO substrate to provide electrical contact to the anode. The coated devices were then transferred, under a 2 atmosphere, into an SPECTROS from Kurt J. Lesker thermal deposition system directly connected to the wet-glove box, for deposition of the electron transfer layer and cathode.

[000194] A schematic of the structure of the OLED device and graphs of the results of the electronic testing are shown in Figu res 15a, 15b, and 15c.

[000195] As can be seen from Figure 15c, the OLEDs employing the random norbornenyl-oxadizole-carbazole as hosts showed reasonable offset voltages of about 8 volts, and were reasonably bright with peak luminance wel l over 10 3 cd/m 2 , and but the observed peak external quantum efficienc ies started at a maximum of about 7%, which declined rapid ly with increasing voltage and current.

[000196] Comparative Example 18 - An OLED Device Employing an Emissive Layer Comprising A Random Styrenic Copolymer of 1 : 1 Styrene- Bisoxadiazole Subunits With Styrene-Triscarbazole Subunits, YZ-IV-25, As Host In the Emissive Layer (6% Ir(ppyh Emitter)

[000197] A similar procedure as detailed in Example 9 was used to prepare an OLED, using a random styrenic copolymer of styrenyl-bisoxadiazole subunits with styrenyl-triscarbazole subunits in a 1 : 1 ratio, see structure below.

[000198] For the emissive layer, 6 wt.% of lr(ppy>3 was m ixed with YZ-fV-25 and both materials dissolved in 1 ml of chlorobenzene (purity of 99.8%; distilled and degassed over night). 40-50 nm thick fi lms were then spin coated (60s@ 1000 rpm, acceleration 10,000 rpm/s) onto the UV crosslinked poly-TPD-F layer. After spin-coating, the samples were baked at 75 °C for 1 5 minutes. Chlorobenzene was then used to remove the emissive layer in the area not covered by poly-TPD-F, exposing the ITO substrate to provide electrical contact to the anode. The coated devices were then transferred, under a N 2 atmosphere, into an SPECTROS from Kurt J. Lesker thermal deposition system directly connected to the wet-glove box, for deposition of the electron transfer layer and cathode.

[000199] A schematic of the structure of the OLED device and graphs of the results of the electronic testing are shown in Figures 16a, 16b, and 16c.

[000200] As can be seen from Figure 16c, the OLEDs employing the random norbornenyl-oxadizole-carbazole as hosts showed reasonable offset voltages of about 8-9 volts, and were reasonably bright with peak luminance over 1 0 3 cd/m 2 , and but the observed peak external quantum efficiencies started at a maximum of about 9- 10%, which declined rapidly with increasing voltage and current.

[000201 ] Comparative Example 19 - An OLED Device Employing an Emissive Layer Comprising A Styrenic Ambipolar Homopolymer Comprising Both Oxadiazole and Carbazole Subunits, YZ-1V-13, As Host In the Emissive Layer (6% Irfppy Emitter) [000202] A similar procedure as detailed in Example 9 was used to prepare an OLED, using a homopolymer of styrenyl-subunits linked to both oxadiazole andcarbazole subunits in a 1 : 1 ratio, s

YZ-IV- 13; Poly(2-(3-(4-vinylbenzyl)phenyl)-5- (3-carba ol-9-ylphenyl)-1.3,4-oxadiazole)

[000203] For the emissive layer, 6 wt.% of Ir(ppy>3 was mixed with YZ-IV- 13 and both materials dissolved in 1 ml of chlorobenzene (purity of 99.8%; distilled and degassed over night). 40-50 nm thick films were then spin coated (60s@ 1 000 rpm, acceleration 10,000 rpm/s) onto the LTV crosslinked poly-TPD-F layer. After spin-coating, the samples were baked at 75 °C for 1 5 minutes. Chlorobenzene was then used to remove the emissive layer in the area not covered by poly-TPD-F, exposing the ITO substrate to provide electrical contact to the anode. The coated devices were then transferred, under a NT atmosphere, into an SPECTROS from Kurt J. Lesker thermal deposition system directly connected to the wet-glove box, for deposition of the electron transfer layer and cathode.

[000204] A schematic of the structure of the OLED device and graphs of the results of the electronic testing are shown in Figures 17a, 17b, and 17c.

[000205] As can be seen from Figure 17c, the OLEDs employing the ambipolar styrenic-oxadizole-carbazole as hosts showed reasonable offset voltages of about 6.5 volts, and were reasonably bright with peak luminance over 10 3 cd/m 2 , and but the observed peak external quantum efficiencies started at a maximum of about 5%, which declined rapidly with increasing voltage and current.

[000206] Comparative Example 20 - An OLED Device Employing an Emissive Layer Comprising A Sryrenic Ambipolar Homopolymer Comprising Both One Oxadiazole and Two Carbazole Subunits, YZ-IV-2L As Host In the Emissive Layer (6% lr(ppy)i Emitter) [000207] A sim ilar procedure as detailed in Example 9 was used to prepare an OLED, using a homopolymer of styrenyl-subunits l inked to both oxadiazole and carbazole subun its in a 1 :2 ratio, see structure below.

Y2-IV-21 ; Poly(2-(3-<4-vinyl enzyloxy)phenyl>-5- (3,5-di(cart3azo(-9-yl)phenyl)-l.3,4-oxa<liazole)

[000208] For the emissive layer, 6 wt.% of Ir(ppy)3 was mixed with YZ-rV-21 and both materials dissolved in 1 ml of chlorobenzene (purity of 99.8%; disti lled and degassed over night). 40-50 nm thick fi lms were then spin coated (60s@ 1 000 rpm, acceleration 10,000 rpm/s) onto the UV crosslinked poly-TPD-F layer. After spin-coating, the samples were baked at 75 °C for 1 5 minutes. Ch lorobenzene was then used to remove the em issive layer in the area not covered by poly-TPD-F, exposing the ITO substrate to provide electrical contact to the anode. The coated devices were then transferred, under a N 2 atmosphere, into an SPECTROS from Kurt J. Lesker thermal deposition system directly connected to the wet-glove box, for deposition of the electron transfer layer and cathode.

[000209] A schematic of the structure of the OLED device and graphs of the results of the electronic testing are shown in Figu res 18a, 18b, and 18c.

[00021 0] As can be seen from Figure 18c, the OLEDs employing the ambipolar styrenic-oxadizole-carbazole as hosts showed reasonable offset voltages of about 6 volts, and were reasonably bright with peak luminance over 10 3 cd/m 2 , and but the observed peak external quantum efficiencies started at a maximum of about 4%, which decl ined rapid ly with increasing voltage and current.

[0002 1 1 ] Example 21 - Synthesis of Polvmerizable Norbornenyl- Phenanth rolinyl Monomers

Step 1 : 2-(4-(tert-butyldimethylsilyloxy)phenyl)-l,10-phenanth roline

[000212] (4-Bromophenoxy)(tert-butyl)dimethylsilane (10 mmol, 3 g) was dissolved in anhydrous THF (20 mL) and the solution was cooled to -78 °C. /-BuLi in pentane ( 1 .7 M, 15 mL, 25.5 mmol) was added dropwise to initiate halogen/metal exchange. After complete addition, the mixture was allowed to warm up to room temperature by removing the cooling bath.

[000213] In a second flask, phenanthroline (5 mmol, 900 mg) was dissolved in 5 mL of anhydrous THF and added to the solution of lithium reagent, then the mixture was allowed to warm up to room temperature by removing the ice/water bath. After stirring for four hours, TLC analysis of the reaction mixture showed phenanthroline disappearance and a new spot appeared (Rf. 0.9, hexane:acetone=2: l ). The dark brown reaction mixture was quenched by pouring it into 5 mL of water, and the color changes into bright yellow. The organic phase was separated and the aqueous phase was extracted with

dichloromethane (2x 10 mL). The combined organic phases were dried over Na 2 S0 4 overnight, then treated with successive additions of Mn0 2 with effective magnetic stirring (4 g). The re-oxidation was easily followed by TLC and the disappearance of the yellow color, and was ended after the addition of another 2 g of Μη0 2 . After the mixture was dried over a 2 S04, the black slurry could be easily filtered on through sintered glass and the filtrate evaporated to dryness by rotary evaporation. The crude material, isolated as yellow oil was purified by column chromatography (50 mL of silica gel, 500 mL hexanes:acetone=3: l as eluant). The solvent was removed from combined desired fractions to give yellow solid 740 mg, 38%).

[000214] (2-(4-(tert-butyldimethylsilyloxy)pheny I)- 1 , 10-phenanthroline): 1 H NMR (300 MHz, CDC1 3 ): δ 9.22 (dd, J= 7.5, 2.1 Hz, 1 H), 8.26-8.21 (m, 4H), 8.03 (d, J = 1 1.0 Hz, 1 H), 7.71 (t, J = 7.5 Hz, 2H), 7.61 (dd, J= 7.5, 4.8 Hz, 1 H), 7.01 -6.98 (m, 2H,), 1.01 (s, 9H), 0.24 (s, 6H). I3 C NMR (75 MHz, CDC1 3 ): «5 157.53, 157.642, 1 50.54, 146.62, 146.25, 136.89, 136.28, 133.19, 129.53, 129.26, 127.34, 126.62, 126.02, 122.98, 120.70, 120.69, 120.39, 25.95, 18.55, -4.09. EI-MS (m/z): M + calcd for C 24 H 26 N 2 OSi, 386.18; found 386.1. Anal. Calcd. for C 24 H 26 N 2 OSi: C, 74.57; H, 6.78; N, 7.25. Found: C, 74.63; H, 6.67; N, 7.19.

[000215] When the reaction was scaled up the reaction to 25 mmol, the yield was about 70%.

[000216] phenol

[000217] A 1 M solution of tetrabutylammonium fluoride (TBAF) (1.55 mmol, 1.55 mL) was added to a solution of 2-(4-(tert-butyldimethylsilyloxy)phenyl)-l,10- phenanthroline (400 mg, 1.04 mmol) in THF (5 mL) at 0 °C. The color turns from colorless to yellow. After 1.5 h, the reaction was quenched by 10 mL water, and white solid precipitated from the mixture solution. The filtered solid was washed with acetone (5 mL) and dried under vacuum to yield 180 mg white solid (yield: 64%). The solid is soluble in DMSO and slightly soluble in methanol, acetone and chloroform.

[000218] 4-(l,10-phenanthrolin-2-yl)phenol: Ή NMR (300 MHz, DMSO): δ 9.87 (S, 1 H), 9.12 (dd, J= 4.2, 1.8 Hz, 1 H), 8.47-8.43 (m, 2H), 8.30-8.23 (d, 3H), 7.92 (dd, J= 9.0, 4.2 Hz, 2H), 7.74 (dd, J= 8.1, 4.2 Hz, 1H), 6.91-6.94 (m, 2H,). I3 C NMR (75 MHz, DMSO): δ 159.78, 156.40, 150.45, 146.27, 145.89, 137.73, 136.88, 130.49, 129.58, 129.50, 127.51, 127.12, 126.43, 123.85, 119.93, 116.31. EI-MS ( /z): M + calcd for C| 8 H| 2 N 2 0, 272.09; found 272.1. Anal. Calcd. for C| 8 H, 2 N 2 0 (JZ-I-125): C, 79.39; H, 4.44; N, 10.29. Found: C, 79.29; H, 4.49; N, 10.29.

[000219] Step3A: Synthesis of : 2-(4-(bicycle[2,2,l)hept-5en-2- ylmethoxy)phenyl)-l,10-phenanthroline

[000220] To a solution of 4-(l,10-phenanthrolin-2-yl)phenol (500 mg, 1.83 mmol) and bicyclo[2,2,l]hept-5-en-2-ylmethyl 4-methylbenzenesulfonate (764 mg, 2.75 mmol) in DMF ( 15.0 mL) was added CS2CO3 ( 1.19 g, 3.66 mmol) at room temperature under stirring. The reaction mixture was heated to 100 °C in oil-bath for 3 h. When reaction mixture was cooled down to room temperature, and water (30.0 mL) was added. The product was extracted with ethyl acetate (20.0 mL x 3), the organic layer was collected and washed with water (50.0 mL x 6). After removal of organic solvents, the crude product was purified on silica gel column by eluting with hexanes/acetone (6:1). After removal of solvent and drying under vacuum, pure product as solid foam was obtained in 540 mg (78.3 %) yield.

[000221] 2-(4-(bicyclo|2,2,l]hept-5en-2-ylmethoxy)phenyl)-l,10- phenanthroline: Ή NMR (300 MHz, CDCI 3) δ): 9.23 (m, 1 H), 8.24 (m, 4 H), 8.07 (dd, J = 8.4, 3.6 Hz, 1 H), 7.75 (m, 2 H), 7.63 (m, 1 H), 7.07 (m, 2 H), 6.21 - 6.00 (m, 2 H, C=C- H, endo and exo), 4.15 - 3.62 (m, OCH 2 , endo and exo, 2 H), 3.08 (s, br, nb, 0.5 H), 2.93 -2.87 (m, br, nb, 1.5 H), 2.60 (m, nb, 1 H), 1.95 (m, nb, 1 H), 1.50 (m, br, nb, 0.5 H), 1.41 - 1.28 (m, nb, 2 H), 0.68 (m, nb, 0.5 H). I3 C NMR (75 MHz, CDCI3): δ 160.88, 157.55, 149.56, 145.15, 145.12, 137.80, 137.62, 137.08, 136.92, 136.91, 136.70, 136.62, 131.76, 131.67, 129.61, 129.57, 127.46, 127.45, 127.13, 125.57, 125.55, 123.08, 120.55, 120.54, 115.01, 72.60, 71.82, 49.68, 45.32, 44.15, 43.95, 42.50, 41.85, 38.82, 38.62, 29.90, 29.30. MS-E1 (m/z): [M] + calcd for C 2 6H 2 2N 2 0, 378.2, found 378.2.

[000222] Step 3B: Synthesis of 2-(4-(5-(bicyclo[2.2.1]hept-5-en-2- yl)penty

[000223] To a solution of 4-(l,10-phenanthrolin-2-yl)phenol (273 mg, 1.0 mmol) and 5-(5-bromopentyl)bicyclo[2.2.1]hept-2-ene (300 mg, 1.2 mmol) in DMF (10.0 mL) was added 2CO3 (270 mg, 2.0 mmol) at room temperature under stirring. The reaction mixture was then heated to 90 °C in oil-bath overnight. The reaction mixture was cooled down to room temperature, and water (30.0 mL) was added, and the product was extracted with ethyl acetate (20.0 mL x 3). The organic layer was collected and washed with water (50.0 mL x 6). After removal of organic solvents, the crude product was purified on silica gel column eluting with hexanes/acetone (6:1). After removal of solvent and dried under vacuum, solid foam was obtained (100 %).

[000224] 2-(4-(5-(bicyclo[2.2.1 ]hept-5-en-2-yl)pentyloxy)phenyl)- 1,10- phenanthroline: Ή NMR (300 MHz, CDCI 3 , δ): 9.22 (dd, J / = 3.6 Hz, J ? = 1.5 Hz, 1H), 8.25 (d, J= 8.4 Hz, 2H), 8.08-8.02 (m, 2H), 7.87 (d, J= 7.4 Hz, lH), 7.56-7.46 (m, 3H), 6.97 (d, J= 8.4 Hz, 2H), 6.07 - 5.85 (m, C=C-H, endo and exo, 2 H), 3.95 - 3.90 (m, OCH 2 , endo and exo, 2 H), 2.70 (s, br, nb, 1.5 H), 1.95 - 1.86 (m, br, nb, 1 H), 1.81 - 1.67 (m, 3 H), 1.42-0.97 (m, 9 H), 0.40-0.45 (m, br, nb, 0.5 H). I3 C NMR (75 MHz, CDCI3): £160.64, 157.16, 150.35, 146.49, 146.13, 137.10, 136.80, 136.22, 132.58, 132.09, 129.44, 129.19, 127.23, 126.54, 125.84, 122.90, 120.03, 114.86, 68.24, 49.77,45.60, 42.71,38.88, 34.88, 32.62, 29.48, 28.64, 26.49. MS-EI (m/z): [M] + calcd for C30H30N2O, 434.2, found 434.3.

[000225] Example 22- Synthesis of a Norbornenyl-Phenanthrolinyl Homopolymer: Polv(2-(4-(bicvcle[2,2,llhept-5en-2-ylpentyloxy)phenyl)-l,10 - phenanthroline)

[000226] 2-(4-(5-(Bicyclo[2.2.1 ]hept-5-en-2-yl)pentyloxy)phenyl)- 1,10- phenanthroline monomer (290 mg, 0.667 mmol), 3 rd generation Grubbs' Ru catalyst, and 5 mL CH2CI2 were mixed together in a dry box and stirred overnight. After removing the vessel from dry box, 1 mL ethyl vinyl ether was added to terminate the polymerization. Precipitating the product solution with ethyl ether (150 mL) results in a purple solid. The polymer was purified by dissolving it into 2 mL dichloromethane, then precipitating it with 150 mL ether. After three precipitations, the color of the polymer is still purple (90 mg,31 %).

[000227] 'HNMR(300 MHz, CDCI 3 ):<S 9.16-9.10 (br, 1 H), 8.27-7.59 (br, 8H), 6.99-6.91 (br, 2H), 5.38-5.23 (br, 2H), 3.99-3.85 (br, 2H), 2.40-2.27 (br, 2H), 1.95- 1.67 (br, 3H), 1.52-1.00 (br, 8 H). [000228] Example 23- An PLED Device Employing an Emissive Layer Comprising A 1 : 1 Blend of A Norbornenyl-Bisoxadiazole Homopolvmer Poly(2-(4- (bicvclo[2.2,l lhept-5en-2-ylpenryloxy>phenyl)-l ,10-phenanthroline)with A

Norbornenyl-Triscarbazole Homopolymer XH-l-98b As Host In the Emissive Layer (6% lr ppy) j Emitter)

[000229] An OLED device employing an em issive layer comprising a 1 : 1 blend of the norbornenyl-phenanthrolinyl homopolymer poly(2-(4-(bicyclo[2,2, l ]hept- 5en-2-ylpentyloxy)phenyl)- l , 10-phenanthrol ine( see Example 22) with A norbornenyl- triscarbazole homopolymer XH- I-98b(see Example 4) as host in the em issive layer (6% lr(ppy)3 emitter) can be prepared by the procedure of Example 9, except that poly(2-(4- (bicyclo[2,2, l ]hept-5en-2-ylmethoxy)phenyl)- l , 1 0-phenanthrol ine is substituted for the electron transporting norbornenyl-bisoxadiazole homopolymer XH- l-98a.

Conc lusions

[000230] The above specification, examples and data provide exemplary description of the manufacture and use of the various compositions and devices of the inventions, and methods for their manufacture and use. In view of those disc losures, one of ordinary ski ll in the art will be able to envision many additional embodiments or sub- embodiments of the inventions disc losed and claimed herein to be obvious, and that they can be made without departing from the scope of the inventions disclosed herein. The claims hereinafter appended define some of those embodiments.